WarblerWatch

Warbler Guy, why is the Olive Warbler in its own family and not in the Parulidae with all the other New World wood-warbler species?

2012-01-19T15:06:00.001-08:00

Primarily because of three reasons (John in Cedar Rapids): 1) The shape of a bone in this species’ skull (the basihyal bone); 2) the arrangement of muscles in the legs; and 3) mitochondrial DNA analysis of this species’ blood indicate its status is far removed from New World wood-warblers (though in the past it was classified with the Parulidae).

In fact, some studies have placed the Olive Warbler in the finch clade (i.e., “group”) that has included finches, cardinals and Hawaiian honeycreeper species.

Given the aforementioned characteristics, the Olive Warbler is
It is the only member of the genus Peucedramus and the only member in the family Peucedramidae.

It breeds from southern Arizona and New Mexico, USA, south through Mexico to Nicaragua.

Another interesting fact: It is the only bird family endemic to North America (including Central America).

Recent DNA studies suggest the phylogenetic (or so-called evolution) of the Olive Warbler split early from the other related passerines, and, indeed, prior to the differentiation of the entire New World warbler/American sparrow/Icterid group.

What does the Olive Warbler eat? As an insectivore, it favors coniferous forest. Some populations are non-migratory, though most New Mexican breeding birds leave the state from November to late February.

Warbler Guy, where are the most abundant numbers of different wood-warblers found?

2012-01-07T12:37:00.000-08:00

Jess (in Chicago), the highest species numbers of breeding wood-warblers are found in the Appalachian, Canadian maritime, and northern Great Lakes regions.

During the non-breeding season, the most common places to find wood-warblers are Mexico, Central America, West Indies, and north to central South America. The farthest known reaches of wintering wood-warblers occurs in Brazil and northern Chile.

Warbler Guy, which warblers are on the U.S. WatchList?

2011-12-10T08:45:00.002-08:00

Frederick (in Naples, FL), here's the four species on the list (compiled via the National Audubon Society, 2007):

Bachman’s Warbler (Endangered)
Golden-winged Warbler
Golden-cheeked Warbler (Endangered)
Kirtland’s Warbler (Endangered)

The U.S. WatchList reflects a comprehensive analysis of all the bird species in the United States, and identifies those in greatest need of immediate conserva- tion attention. The list builds on data from Partners in Flight (PIF), the latest research from the bird conservation community, and data from the Christmas Bird Count and Breeding Bird Survey.

Identifying and spotlighting the species at greatest risk is the first step in building the public policies, funding support, conservation initiatives, and public commitment needed to save them. The U.S. WatchList lays the groundwork for an “industry stan- dard” to guide conservation priorities among conservation organizations and government agencies.

Fab Five Warbler Quiz #6

2011-11-05T15:23:00.009-07:00

Can you name each of the five warblers? (A helpful hint: not all the warblers in these photos are males.)

Warbler Guy, where are warbler photos best found on the Web? Where may I compare and contrast warbler images online?

2011-10-18T18:15:00.002-07:00

Jason (in Buffalo), I recommend the web site operated by Giff Beaton in Georgia.

Giff's "Warblers" site is found at:

http://www.giffbeaton.com/warblers.htm

Recent systematic name changes in the warbler family are also present in the way Giff organizes his photos, so
information is updated according to the latest American Ornithological Union (AOU) decisions.

His site also features links to bird-related sites; information and photos related to dragonflies and insects; and links to other nature topics (See: http://www.giffbeaton.com/index.html)

And Then There Was One: Connecticut Warbler Now Widow-Widower

2011-10-03T22:42:00.006-07:00

Given the American Ornithological Union's (AOU) recent scientific name changes for wood-warblers (noted in the 9/28/11 article, immediately below),
all of the Oporornis genus members are now gone.

Except one.

The Connecticut Warbler remains as the lone Oporornis representative. (Kentucky, Mourning, MacGilliviray's were subsumed into the Geothylpsis genus that formerly in N. America merely consisted of the Common Yellowthroat.)

During the nesting season, the often stealth, ground-dwelling Connecticut Warbler is frequently confidently ID'ed by savvy birders who know it walks (along with only four other N. American wood-warbler species). The large eye ring is another prominent feature. Notice how the throat color pattern differs from the look-alike Nashville Warbler, which features yellow throughout the throat (in contrast to the gray throat/chin sheen in Connecticut).

Most Connecticut individuals have already left the USA as obligate neotropical migrators that will spend the non-breeding season amid the Amazon River area in South America.

Next spring, this species is one of the last wood-warblers to return to breeding rounds and, thus, is considered
a late migrant in comparison to other earlier arriving USA wood-warbler species.

What are the latest bird name changes or warbler name changes? When did the American Ornithological Union (AOU) approve these names?

2011-09-28T04:50:00.003-07:00

Yes, Aaron (in Akron, OH), the 52nd AOU Checklist Supplement approved and published in 2011 lists the following wood-warbler changes to species names (INCLUDING the scientific name change for the wood-warbler shown in the nearby photo, the common name of which is the answer for the one-click quiz on the left side. As a hint, we're still playing taps on our bugle, given the Wilsonia genus is now R.I.P., subsumed into the genus occupied by the Red-faced Warbler (Cardellina genus).):

• Mourning Warbler Geothlypis philadelphia
formerly Oporornis philadelphia
• MacGillivray’s Warbler Geothlypis tolmiei
formerly Oporornis tolmiei
• Kentucky Warbler Geothlypis formosa
formerly Oporornis formosus [note change in spelling of species name]
• Hooded Warbler Setophaga citrina
formerly Wilsonia citrina
• Kirtland’s Warbler Setophaga kirtlandii
formerly Dendroica kirtlandii
• Cape May Warbler Setophaga tigrina
formerly Dendroica tigrina
• Cerulean Warbler Setophaga cerulea
formerly Dendroica cerulea
• Northern Parula Setophaga americana
formerly Parula americana
• Tropical Parula Setophaga pitiayumi
formerly Parula pitiayumi
• Magnolia Warbler Setophaga magnolia
formerly Dendroica magnolia
• Bay-breasted Warbler Setophaga castanea
formerly Dendroica castanea
• Blackburnian Warbler Setophaga fusca
formerly Dendroica fusca
• Yellow Warbler Setophaga petechia
formerly Dendroica petechia
• Chestnut-sided Warbler Setophaga pensylvanica
formerly Dendroica pensylvanica
• Blackpoll Warbler Setophaga striata
formerly Dendroica striata
• Black-throated Blue Warbler Setophaga caerulescens
formerly Dendroica caerulescens
• Palm Warbler Setophaga palmarum
formerly Dendroica palmarum
• Pine Warbler Setophaga pinus
formerly Dendroica pinus
• Yellow-rumped Warbler Setophaga coronata
formerly Dendroica coronata
• Yellow-throated Warbler Setophaga dominica
formerly Dendroica dominica
• Prairie Warbler Setophaga discolor
formerly Dendroica discolor
• Grace’s Warbler Setophaga graciae
formerly Dendroica graciae
• Black-throated Gray Warbler Setophaga nigrescens
formerly Dendroica nigrescens
• Townsend’s Warbler Setophaga townsendi
formerly Dendroica townsendi
• Hermit Warbler Setophaga occidentalis
formerly Dendroica occidentalis
• Golden-cheeked Warbler Setophaga chrysoparia
formerly Dendroica chrysoparia
• Black-throated Green Warbler Setophaga virens
formerly Dendroica virens
• Fan-tailed Warbler Basileuterus lachrymosus
formerly Euthlypis lachrymosa [note change in spelling of species name]
• Canada Warbler Cardellina canadensis
formerly Wilsonia canadensis
• Wilson’s Warbler Cardellina pusilla
formerly Wilsonia pusilla

In addition, see the following web site written by David Sibley to learn more about wood-warbler name changes and the rationale for the new taxonomy that the American Ornithological Union recently approved:

http://www.sibleyguides.com/2011/06/the-new-wood-warbler-taxonomy/

Warbler Guy: Where's warbler resources online? Warbler books? Warbler field guides? Warbler information?

2011-09-20T05:33:00.005-07:00

Jeremy (in Austin, TX):
Feel free to check out:

http://www.virtualbirder.com/vbirder/onLoc/onLocDirs/BOSSPR/shelf/index.html

Warbler resources are also listed in the bibliography within the Warblers field guide (shown here as a graphic) by Jon Dunn and Kimball Garrett (1997, Houghton Mifflin).

Of course, tooting my own riff: I present warbler-centric slide shows when invited by groups. More information about these shows is at my web site:
www.warblerwatch.com

Enjoy the warblers, Daniel

Are Pt. Reyes & the Farallon Islands the best W. Coast spots to see E. Coast vagrant warblers? Is it rare to see CT Warbler in CA?

2011-09-13T19:44:00.004-07:00

Excellent questions, Jason. Answers: 1. The book “Rare Birds of California” is an excellent resource for your questions. CT Warbler is a rare vagrant at the spots you mention, though it’s also been recorded as a vagrant from s. British Columbia south to n. Baja CA. Vagrants have also been seen in C. America and the western Caribbean. The initial confirmed record of CT in California was a spring male collectedon June 16, 1958 on southeast Farallon Island, a location that claims first state records of five other wood-warbler species.

True fact (that is amazing): More than half of CA’s CT sightings originate from one rock on southeast Farallon Island.

Vagrant (“accidental”) warbler species are NEVER common on the West Coast, but they are always annually seen. Point Reyes National Seashore is often a fine place to see them in September and October, especially within Monterey Cypress groves that occur sporadically within and near ranches on the way to the Outer Point/Lighthouse area within the park. Foggy/cloudy days are often the best conditions to see “layover” individuals. Some of the best areas to visit in pursuit of vagrant East Coast warblers here include the Drakes Beach, Chimney Rock, and Lighthouse areas.

Connecticut Warbler is currently present (on 9/12 and 9/13/11) in the Monterey Pine groves within Point Reyes National Seashore near Chimney Rock.

To find this location, contact the park's rangers or email me: danieledelstein@att.net

Warbler Guy, where is bird radar migration information? Bird migration radar maps? Radar information related to birds?

2011-09-04T22:32:00.004-07:00

Joey (in Hamilton, Ontario): There's a great bird radar migration web site at:

http://virtual.clemson.edu/groups/birdrad/

Here, you'll find how the Clemson Radar Ornithology Laboratory and its latest work related to:

-Calibrating WSR-88D displays for quantifying bird migration,
-Developing migration maps for different regions of the United States,
-Examining changing migration patterns with comparisons of current and historic radar datasets,
-Developing national migration models from forecast weather variables,
-Forecasting bird migration in the northeastern United States (BIRDCAST),
-Identifying and delimiting important migration stopover areas by using WSR-88D and classified multispectral satellite data in a GIS,
-Mapping roosting areas of Purple Martins throughout the South, and
-Conducting radar studies of bird migration through Panama.

Another related, albeit regional bird migration site for the autumn/post-breeding movement of songbird is:

http://minnesotabirdnerd.blogspot.com/

Currently, excellent "difficult fall warbler" photos are shown at this blog site (in the 8/30/11 article and corresponding photos).

Warbler Guy, which vagrant is the "coolest" to see in the West this autumn?

2011-08-13T11:57:00.004-07:00

Many vagrant, East Coast/Midwest nesting wood-warblers are eye catching prizes to see
during the post-breeding season, among them the Connecticut Warbler shown here.

The more rare to uncommon (vagrant) ones seen at places such as Point Reyes National Seashore and its Outer Point and Lighthouse
area include:
- Cerulean Warbler
- Black-throated Blue Warbler

Which so-called East Coast warblers are the most common vagrant species to see in this area?

- Palm
- American Redstart
- Tennessee
- Blackpoll

Wisconsin Kirtland's Warbler Nesting Update

2011-08-04T09:26:00.002-07:00

In 2011, Kirtland’s Warbler was recorded in five counties in Wisconsin. Biologists documented a minimum 22 male and 11 female individuals in the state. Among 11 nesting attempts, four nests were successful, fledging an estimated nine to 17 young throughout the state.

At least 1,840 male Kirtland's Warbler now exist, a small total number. BUT an amazing comback for the federally-endangered wood-warbler that was once on the brink of extinction.

More details soon.

Please check back to learn more about this exciting annual nesting phenomenon.

Warbler Guy, When does Kirtland’s Warbler migrate south? The Kirtland’s Warbler migration is early? Or does Kirtland’s Warbler migrate in fall?

2011-07-26T09:42:00.003-07:00

Actually, Jeremy (in Detroit), many of the Michigan-based nesting Kirtland’s Warblers disperse and migrate by July (and no later than August). Look for them in mid-July where they nest in central Michigan counties and you’ll often be out of luck. In fact, their nesting period is a small window of time, typically from their mid-May arrival through the subsequent next six to eight weeks.

Then dispersal may happen before mandatory (or obligate) migration occurs. Think of dispersal as local to short-distance travel away from the nesting area. This interim period involves feeding and molting prior to the Kirtland’s long night-time migration to the Bahama Islands.

Followers of this blog may also know that Kirtland’s Warbler now nest annually in Wisconsin. (See articles from May and June, 2011, below.) Wisconsin Kirtland’s Warbler individuals also usually leave their nesting grounds in July. They, too, eventually migrate to the Bahamas, thereby joining Michigan nesters for the non-breeding season.

How many Kirtland’s Warblers exist? Probably no more than approximately 1,825 to 1,850 males, according to recent combined breeding bird studies that incorporate totals from Michigan and Wisconsin. One annual nesting spot in Ontario also occurs for this federally endangered wood-warbler.

What's this photo's ID (of a hybrid warbler recently present at Summer Lake in south-central Oregon)?

2011-07-17T19:49:00.006-07:00

(photo (c) Jim Arneson via flickr)

Answer:

My guess is as good as yours, though my initial thought is a form of Canada Warbler, given the trace of the necklace and eye ring typical of a classic male Canada Warbler.

Other field marks suggest Black-throated Blue, American Redstart and either Mourning or MacGillivray's.

Someone suggested the cross/intergrade appearance is most closely alligned with Junkin's Warbler, meaning it shows
field marks associated with Mourning and Kentucky.

Your thoughts?

Warbler Guy, what's this newborn West Coast warbler's ID?

2011-07-17T18:03:00.007-07:00

....and the BIG hint for the nearby photo is its name begin with "Black-......"
(Remember, it's a West Coast wood-warbler species)

You can enter your answer in the "comments" section below.

Or you can vote at the nearby quiz on the right column.

Warbler Guy, what are the new warbler name changes? Do only the scientific names change and the common names remain the same?

2011-07-04T13:41:00.005-07:00

Excellent question, Noah. (Warbler "taxonomy tree" name chart is difficult to read here, but is easier to see at the
link noted below in the final sentence.)

The honest and best answer is for you to read David Sibley’s account (David Sibley's blog = http://www.sibleyguides.com)

His summary of the warbler name changes is the best account I’ve read.

You can see it at:

http://www.sibleyguides.com/2011/06/the-new-wood-warbler-taxonomy/

Happy 4th of July...(As we celebrate, by the way, millions of wood-warbler newborns are flying for the
first time today in northern latitudes. Some (such as LA Waterthrush that nested in the mid-Atlantic) are already dispersed and migrating nearby their nesting grounds and/or south by this time and this month.

Warbler Guy: Is the Yellow-Breasted Chat still a wood-warbler? Or did it get “kicked out” of its family? Why is the chat a wood-warbler?

2011-06-28T06:11:00.001-07:00

Yes, Earl (in Tacoma, WA): No ex-communication for the black sheep of the wood-warbler family….Per the upcoming AOU (American Ornithological Union) “check-list committee,” the Yellow-breasted Chat will remain classified as a wood-warbler in the family Parulidae. This information is courtesy of the ABA’s Paul Hess.

Mr. Hess also wrote in the ABA’s blog recently that “the annual check-list supplement to be published in July will merely point to recent mitochondrial DNA analyses indicating that the chat's genus (Icteria) represents an old (evolutionary) lineage of uncertain affinities, probably related to the Parulidae, Icteridae, or Emberizidae (families).

He concludes: “In retrospect, I suppose the status quo shouldn't be surprising.” (i.e., that the chat is NOT yet ejected from its family, given the more than two-inch size difference and larger bill size it possesses in comparison to the other 106 wood-warblers).

“After all, the (check-list) committee did not receive a formal proposal in the past year that explicitly recommended moving the chat out of the Parulidae.”

Yellow-rumped Warbler Split?: No

2011-06-16T03:21:00.002-07:00

. . . AOU votes down splitting Yellow-Rumped Warbler into two, three or four species

(Audubon's Yellow-rumped subspecies appears in photo.)

As many of you already know, the Yellow-rumped Warbler currently occurs as four subspecies, according to many researchers: the “Myrtle” group (coronata), and the “Audubon’s” group (auduboni), “Black-fronted” (nigrifrons), and “Goldman’s” (goldmani)

The taxonomy of these Yellow-rumped Warbler subspecies was under consideration for change by a committee in the American Ornithologist Union (AOU).

Now the vote is in.

No hanging chads here.

The vote was 7–4 against any divisions of the Yellow-rumped complex. The committee members suggested the need for further genetic analysis and determination of the extent of interbreeding in the subspecies’ contact zones where the “Myrtle” group (coronata), and the “Audubon’s” group (auduboni) mix in western Canada. The status of two other subspecies — “Black-fronted” (nigrifrons), and “Goldman’s” (goldmani) remain unchanged.

Black-fronted is a resident in Mexico, and Goldman’s occurs only in southernmost Mexico and Guatemala. Neither of these two subspecies has been observed in the American Birding Association geographical area.

Five & Counting: Wisconsin Kirtland's Warbler Nests For Fifth Consecutive Year in the State

2011-06-02T22:27:00.009-07:00

Wisconsin Kirtland's Warbler Update *

(* = 2011 Kirtland's Warbler Nesting Success in Wisconsin; photo courtesy of Joel Trick)

Go to the following web site if you'd like to find out more about the 2011 Kirtland's Warbler nesting success for the current breeding season:

http://www.fws.gov/midwest/greenbay/

Given the amazing comeback of this federally endangered species, it's safe to suggest (with tongue firmly planted in tongue of cheek) that the Kirtland's wins the Comeback Bird of the Decade for its rebound to more than 1,800 males among the nesters occurring in Wisconsin, Michigan and Ontario (where in the latter place one location appears to annually host a breeding population).

For Wisconsin, the above the fold headline is already exclaimed above:
It's the FIFTH year in a row that Kirtland's has nested in the Bucky Badger state.

That's an unprecedented development for the species, which, as you may know, was thought until its discovery as a nester in Wisconsin in 2007 to ONLY
annually breed in Michigan.

There it was previously considered to be an endemic, with the entire population migrating to the Bahamas for the "winter."

Lastly:

Plenty of thanks should be extended to volunteers who monitor the federally endangered Kirtland's Warbler.

It's their efforts that continue to daily monitor the Kirtland's in Wisconsin as you read this item.....with the U.S. Fish & Wildlife Service's Joel Trick leading the crew.
Kudos to Joel Trick for helping an endangered species widen its territory as new habitat was found by Mr. & Mrs. Kirtland's arriving from the Bahamas each May (ostensbily, Jack Pine groves with an assist from Pinus cousin rubra, Red Pine, where the species is also found in WI)

Warbler Guy, which bird apps are the best ones? Are apps for birds worth their price? Is iBird Pro app better than Peterson Birds of N. America?

2011-05-26T20:30:00.004-07:00

Good question, Harrison (in Tacoma).

I like and use a few.

My faves include (in order of preference):

1. Peterson Birds of North America, Appweavers.com ($29.99)
This one has premium features that make it easy to navigate, plus you can enter your own
sightings to create lists that provide you an ongoing journal of your birding forays. This feature alone helps personalize
it and provides an interactivity that is missing in the other apps. Plus, you can "talk" with your birding friends to compare and contrast how your day's list of bird sightings is different from theirs.

2. iBird Pro ($29.99), ibirdexplorer.com
When it's quick access you need to hear a bird sing, then this is the app you should draw from your holster.
Its simple, easy design makes it a pleasure to use, with the premium edition (this one) more pricey ($29.95)
than many bird apps, yet worth the price. Photos of a bird, its range map, information, vocalizations and more
present for more than 600 species.

3. Sibley Guide to birds of North America ($29.95), http://www.mydigitalearth.com
Featuring more than 6,600 bird images and 2,300 song files. My favorite feature is the visual representation of each succeeding age class among multiple gull drawings featured in the Laridae family area.

Warbler Guy: Do you agree that "HeadsUp Warblers" is a “Thumbs-Up” new app?

2011-05-21T21:59:00.004-07:00

Yes, given I read review of it in the May, 2011 Birding Magazine (www.ABA.org), page 64, “HeadsUp Warblers: An App by the Makers of birdJam."

In response, I bought it for a mere $7.95 at the
iTunes store that is reached via www.apple.com)

Verdict: Nice job, birdJam folks.

Plenty of reasons to buy it, whether you're a beginner or advanced warbler-watcher.

Full disclosure: I have no economic connection with birdJam, but I do have this one self-admitted popular
wood-warbler blog site.

Populating it with info. about wood-warblers is the mission.

A similar spike in warbler fans pledging allegiance to "HeadsUp" won't be too hard for birdJam, based on its latest-greatest.

BTW:

What are my readers' thoughts on the quality of HeadsUp Warblers? Feel free to post a comment, below, so
that we'll know where you stand on this new title.

Enjoy the wood-warblers.....(If you're reading this at night in a far northern USA latittude, then millions of ww's are currently passing through your area.)

Warbler Guy, does the spring Blackpoll Warbler migration distance equal its long distance trek in the fall?

2011-05-13T23:18:00.003-07:00

Yes, Amy (in Baton Rouge), for some populations, Blackpoll’s north and southward migration routes are likely the longest of all wood-warbler family members. The well-noted 2,150 autumn migration distance some New England Blackpoll partake in the autumn as trans-ocean migrants is a breathtaking marvel. Seventy-two to 90 continuous hours of migration over the ocean by a half-ounce bird seems an impossible feat. But imagine the current spring-time migrants (see graphic, courtesy of the borealbirds.org and the map created by eNature, which is supported by The Pew Charitable Trusts). Some travel 100-150 miles per night, with some doing so for weeks and eventually reaching Alaska after beginning their path in n. South America. Equally awe-inspiring, correct?

Warbler Quiz Answers: Latest Ones On Right Side Of This Page

2011-05-06T19:45:00.002-07:00

You're a warbler quiz wiz?

You be the judge, as here's the answers to the most recent warbler quizzes (that appear on the right column as you scroll down from one to the next).

- Quiz Question:
(Myrtle) Yellow-rumped Warbler are one of the initial wood-warblers to return at northern latitudes in the USA because:

ANSWER: all of the above

- Quiz Question:

Unlike the majority of USA warblers that are trans-gulf migrants, the following species shuns over-water flight and, instead, uses C. Am. & Mexico to reach USA breeding grounds:

ANSWER: Nashville Warbler

- Quiz Question:

Which wood-warbler is documented to periodically eat fish?

ANSWER: Louisiana Waterthrush

- Quiz Question:

By the first week of March, which returning wood-warbler is the second or third most abundant wood-warbler species in the USA?

ANSWER:

Orange-crowned Warbler, as the majority of West Coast neotropical migrants typically return to breeding grounds by early to mid-March (with the initial pulse often occurring in late February, depending on latitude).

Did you see the warbler chapter in the newly updated book by Kenn Kaufman, A Field Guide to Advanced Birding?

2011-04-29T23:09:00.002-07:00

Yes, Amy (in Orlando): Kenn Kaufman’s update (from his original and now classic original A Field Guide to Advanced Birding) hosts an excellent chapter devoted to wood-warblers titled “Learning to Identify Warblers”

This insightful chapter is divided into subthemes such as “How To Look At Warblers,” “Learning The Groups of Warblers,” “What To Look For In Identifying Warblers,” and “Understanding What You Hear: Warbler Voices.”

Especially well done is Kaufmann’s explanation of warbler songs that he notes consists of two major song types in many warbler species.

He also expertly delineates the difficult autumn plumage ID challenge of the “Blackpoll Trio” consisting of Blackpoll Warbler, Bay-Breasted Warbler, and Pine Warbler.

HEY Warbler Guy: When's "Peak" Warbler Watching in Florida During Spring? Warblers in Florida Are Common Now?

2011-04-21T06:35:00.002-07:00

Indeed, Michael in Mobile, AL:

Note the current Prime Time Parade of warblers in Florida needs a new publicity director?

Or maybe the following excerpt from a post by Mr. John Thornton at Birding On The Net will get people's warbler watching passion to boil over with intrigue?:

Subject: Leu and Mead Gardens (4/20/11)
From: John Thomton
Date: Wed, 20 Apr 2011 19:20:29 -0500

Hey everyone,

It's peak migration now, so I thought if I'm a birder worth my salt, I better
be out there if I had the chance! I did make myself go running this morning
before birding, because I knew I wouldn't want to in the heat of the day AFTER
birding. Consequently I arrived at Leu at about 9:45 AM and then at Mead around
1:00 PM (left about 2:30). It wasn't crazy today, but never boring. There was
so much breeding bird activity, I was always entertained even if it wasn't a
non-stop migrant show. I did hear the Yellow-Breasted Chat at Mead briefly and
I saw him flush, but I never got a good look. Here's the warbler species list:

Northern ParulaCape May Warbler (1 male,
Leu)Black-Throated Blue Warbler (2, 1 male and 1 female, Leu)Blackpoll Warbler
(1 female, Leu)Black-and-White Warbler (3, Leu; 2, Mead)American Redstart (1
female, Leu; 2 males, Mead)Ovenbird (1, Leu)Common Yellowthroat (1, Leu; 1,
Mead)Yellow-Breasted Chat (mostly heard only, not good looks like at Orlando
Wetlands a few weeks ago.

It's still been a thrush-less spring migration for me, so far. Also I was a
little surprised I couldn't come up with a Turkey Vulture for the day!

Leu Gardens is located near the intersection of US 17/92 (Mills Ave.) and
Virginia Ave. in northern Downtown Orlando. There is an entrance fee for
non-members (but again, if you are a member of your local botanical gardens or
arboretum, you may get reciprocal free entry). Mead Garden is located near the
intersection of US-17/92 (Orlando Ave.) and Orange Ave. in Winter Park. There
is no entrance fee.

Good birding,
John ThomtonOrlando, Orange Co.

Warbler Guy: Is it true that proposed changes by the AOU may drastically change the classification of wood-warblers?

2011-04-16T01:13:00.004-07:00

Yes, that's the "flash" news scroll across my Warbler Network TV cable station, too....though NO "flash" scroll new for folks reading this blurb and ALREADY updated from the American Birding Association's (ABA) BIRDING
MAGAZINE “News And Notes”section
(March, 2011, page 25-26) relating to:

The switch of 21 species in largest USA-based wood-warbler genus — Dendroica — to the current American Redstart genus, Steophaga.
In the new grouping (or clade, the technical term),
all of these 21 species join
N. Parula, Tropical Parula,
Am. Redstart, and Hooded Warbler.

Obviously, bye-bye to Dendroica and hello to Setophaga on the leader board for wood-warblers,
IF this new classification scheme proposed by Cornell Lab of Ornithology’s
Irby J. Lovette and his 11 colleagues is approved.

Worse (and get out the hanky), Yellow-breasted Chat will no longer be considered a wood-warbler, IF the proposed changes happen.

Stay tuned.

One last, brief update…..Instead of 115 New World wood-warblers
{per Dunn & Garrett’s theory in Warblers, their 1997 field guide
(in need of updating, by the way)},
Lovette, et al propose 107 species as New World wood-warbler members.
These form 14 genera, they suggest.

(NOTE: One Dendroica genus member, the Yellow-rumped Warbler, has four subspecies associated with it. For the latest report about this name division, see the article at this blog dated 3/7/11 "CORRECT Yellow-Rumped Warbler Species Name Update....")

WARBLER GUY: Was that you I saw in the Minny-apple Tribune?

2011-04-16T01:09:00.003-07:00

Yes, Amy: I'm now highlighted beyond my photos on post office walls, as, it's true:

The Minneapolis Tribune and its venerable outdoor/naturalist columnist Jim Williams
evidently think people like wood-warblers.

Who woulda thunk? -- and, indeed, you can see me featured in all true modesty at:

http://www.startribune.com/lifestyle/homegarden/blogs/119534269.html

Good warbler watching, everyone.....Daniel, The Warbler Guy:
edelstein@earthlink.net
warblerwatch.com

Warbler Quiz #6: Test Your Warbler Migration, Warbler Behavior, and Warbler Identification (Warbler ID) Skills (Answers at bottom of this article.)

2011-04-05T21:07:00.005-07:00

a. True or False: Female wood-warblers never sing?

b. Fill in the blank: Beyond insects, warblers primarily eat two other general kinds of food: seeds & XXX (Please type your answer here).

c. True or False: All North American (New World) warblers migrate?

d. Choose one answer from the two options in the following question: In addition to approximately 52 species of warblers breeding in the United States north of Mexico, there’s a (smaller) (larger) number of species that breed in the tropics?

e. True or False: Some warblers species travel more than 100 miles per night during migration?

Answers:

a. At least two female New World wood-warbler species are believed to sing:
Yellow and American Redstart.

b. Fruit

c. False. Common Yellowthroat {a common breeder/nester in every USA state (except HI) and Canadian province) does not migrate from SOME of the places where it breeds in southern portions of its breeding range} is one example of a non-migrating wood-warbler species.

d. Larger (107 New World wood-warblers exist, so a greater/larger number occur as nesters in the tropics than the number breeding in the United States north of Mexico.)

e. True. Depending on many factors, including weather and wind, some neotropical songbird migrants (including warblers) may travel as much as 100-150 miles on a single night’s migration.

Sweet Tweet By Me: Utilizing Warblers' Undertail Covert Patterns For ID

2011-03-24T05:25:00.008-07:00

Here's my latest tweet via Twitter relating to the above title/subject:

Spring Fever Cure: Helpful, Sometimes Diagnostic Wood-Warbler Feature = Undertail Patterns/Undertail Coverts: see pgs. 104-106 in “Warblers” (Dunn & Garrett, 1997).

(CLICK ON THE nearby illustration of the bird to see a closer view of its "undertail covert region." More specific, undertail marks on the bottom (ventral) side of the tail feathers (rectrices) are a diagnostic field mark in some species of New World wood-warblers (e.g., Magnolia Warbler, shown here, with abrupt demarcation/border of white-black)

LASTLY:

PLEASE note you can follow me on Twitter at:
@edelstein1
(but who has the time or the interest? I'd rather watch birds than tweets, correct!? So I'm off to bird and find the latest returning neotropical migrants to our Marin Co. area.)

Latest Quiz Answers (right side of page and scrolling down)

2011-03-20T22:20:00.005-07:00

....are the following (and corresponding to the second most recent quiz on the right side of this article and scrolling down to older quizzes):

By the first week of March, which returning wood-warbler is the second or third most abundant wood-warbler species in the USA?

Answer: Orange-crowned Warbler. Why? Given the first week of March is too early for the bulk of returning Yellow Warbler and Louisiana Waterthrush to breeding sites, and given Yellow-breasted Chat is typically only common in localized areas (and rare to uncommon throughout much of its formerly larger breeding range), Orange-crowned’s begin appearing in portions of its breeding range by late February/early March. Note these returning breeding Orange-crowned are true migrants beyond the small population of this species that appear to overwinter during the non-breeding season. (Note #2: One Orange-crowned subspecies is a resident in the central CA coast, so it’s not intended to be included in this quiz question dynamic.)

“Second or third most abundant wood-warbler species in the USA” as the quiz question accounts for the more abundant numbers of Yellow-rumped Warbler and Common Yellowthroat in the USA during the initial portion of March, if only the USA is considered.

*

Which subspecies' breeding range is larger?: Audubon's Yellow-rumped or Myrtle Yellow-rumped Warbler?

Answer: Myrtle. See any range map for this species (e.g., "Warblers," Jon Dunn/Kimball Garrett, Houghton Mifflin, 1997). Note the vast area
throughout most of Canada and ALL of Alaska where Myrtle breeds.

*

Can you identify the correct order (top to bottom) of wood-warblers in the five photos on the left from the 11/10/10 posting?

Answer: Black-Th. Gray, Canada, Palm, Orange-crowned, Cape May.

*

In how many states does Kirtland's Warbler regularly nest?

Answer: Michigan and Wisconsin, with the Badger state now hosting breeding Kirtland’s during the last four consecutive breeding seasons. Previously, Michigan was thought to be the only state hosting annually occurring breeding populations for this species.

Warbler Guy, which books show warbler feathers and reveal warbler molt strategies?

2011-03-13T20:12:00.004-07:00

Great question, Harold C. (Fargo, ND).

Finding stray birds' feathers is often both a pleasant and vexing discovery. It's pleasant because finding a feather is a nice treasure to stumble upon on the trail. But then the question often beckons upon examining your find: To which species does this feather belong? Let the identification bidding begin: Do I hear W. Scrub Jay? Stellars Jay? Over here in this corner: W. Bluebird? Hmmm....so many choices for blue-appearing feathers alone.

What's one to do?

The second citation, below, is one remedy.

Another helpful guide to identifying birds when finding feathers or, in general, expanding your understanding of bird biology/birds' life cycle is the initial reference book, below.

Here's their citations (as they've helped me often recently as I continue reading and utilizing them regularly for my work):

1. Peterson Reference Guide to Molt in North American Birds. 2010. Steve N.G. Howell. Houghton Mifflin Harcourt Publishing Company. New York, NY 10003 (www.hmhbooks.com).

2. Bird Feathers: A Guide to North American Species. 2010. S. David Scott & Casey McFarland. Stackpole Books. Mechanicsburg, PA 17005 (www.stackpolebooks.com)

Warbler Guy, which warbler DVD is excellent to watch so that I can identify warblers (and use as warbler identification media)?

2011-03-08T10:52:00.002-08:00

Thanks to Eric Salzman, the answer is in a recent “Winging It” newsletter (June, 2010) where Eric highlights two EXCELLENT warbler DVDs:

“Watching Warblers” (Judy Feith & Michael Male, Blue Earth Films, www.birdfilms.com, $35) and “Watching Warblers West” (same people/source as the line above, $35).

Both titles are awe-inspiring. Synthesizing thousands of hours in the field with their cameras, Feith and Male are consummate filmakers that add an exquisite dash of splendor with images of warblers feeding, nesting, bathing, etc. Jaw-dropping warbler scenes are all "G rated" for my adult students to enjoy, especially on a rainy day when my workshop/class is forced to remain sequestered indoors in lieu of sleuthing for warblers outdoors.

A cool element on both DVDs: each contains “extra” features, including running clips of single males belting out their songs in mini-episodes called “Fun With Songs.”

Summary: Thumbs up. Way up.

Enjoy spring’s beginnings. Recrudescence ho….Warblers, start your flying engines.

CORRECT Yellow-Rumped Warbler Species Name Update....

2011-03-07T09:27:00.003-08:00

....and given recent changes, please note some of this blog's past Yellow-rumped Warbler
articles are either now wrong and/or out of date.

So, please note the most current, accurate Yellow-rumped Warbler nomenclature
appears at the 1/26/11 article, below.

Past articles about this species from 10/10/09, 10/5/09, and 7/8/09 are no longer necessarily
correct, in terms of the subspecies names associated with the Yellow-rumped Warbler species.

Please read the 1/26/11 article for more precise direction you can take to learn more.

Now back to your wood-warbler questions, with many to answer after I go birding.....Cheers, Daniel

Warbler Guy, do female warblers sing? If so, which female warblers have songs? Or do only male warblers sing?

2011-02-26T18:40:00.001-08:00

Nice question, Bernice (in Mondovi, CA).

At least nine species of temperate zone wood-warblers (representing six genera: Vermivora, Dendroica, Setophaga, Seiurus, Geothlypis, and Wilsonia) have been confirmed as singers based on field studies (Evans Ogden, Neudorf, Pitcher, and Strutchbury, 2003).

Given merely a minority of females sing among the world’s 4,000+ songbird species, what’s the payoff for this vocal behavior? One theory is that female singers may be adopting male-like behavior, especially among older females (Nolan, 1978). Another theory suggests female song results from female-female conflicts occurring in dense populations (Hobson and Sealy, 1990) or may be a function in intra-pair contact (Gilbert and Carroll, 1999).

Among the singing wood-warblers in the U.S., Dunn & Garrett state in Warblers (1997) that Yellow Warbler (ABOVE photo, a female, courtesy of the US Fish & Wildlife Service) song has been documented in at least one population in Manitoba, Canada (Dunn & Garrett, 1997).

Likewise, these two authors suggest in the same field guide that American Redstart females sing sporadically to rarely (if at all).

FAB FIVE WARBLER QUIZ #4

2011-02-05T09:52:00.011-08:00

Can you identify the wood-warblers in each of the following five photos?....
(by clicking on the "Post A Comment" and listing them in order from the topmost photo through to the bottommost one) Note that you can click "anonymous" to "Post A Comment" and, if you wish, leave your name and city at the bottom of your warbler identity list.

Warbler Guy, which wood-warbler sang first in the movie The Social Network's sound track background? Why was it probably the wrong species?

2011-01-31T00:37:00.004-08:00

Good question, Dr. Watson? -- err, I mean Erica (in Palo Alto, CA).

Indeed, long antennae make fine decisions when identifying birds by ear.

So how could a Wilson's Warbler (ABOVE photo) sing near Harvard's campus in the crew racing scene that appears
soon after The Social Network begins?

This vexing question is valid because Wilson's only passes through the Harvard University area (Massachusetts) as a spring and fall transient.

BUT the scene in the movie depicts a summer atmosphere, post migration, when Wilson's would already be farther north on breeding grounds.

Ho-hum. Another movie that cares little that birders compose a portion of the audience.

We are listening, Hollywood. You have it wrong. Our antennae are long.

Film on the floor. Cut up.

Take 2.

Warbler Guy, what are the latest AOU species split proposals? Are Yellow-Rumped Warbler subspecies going to change in number?

2011-01-26T07:14:00.003-08:00

(UPDATE: The article below is outdated, given recent name classification changes. Thus, see the 3/7/11 article here at this blog for an update in relation to the Yellow-rumped Warbler split into various subspecies.)

*

There's an excellent article to read All About It, Robert Z., if you go to:

http://docs.google.com/viewer?a=v&q=cache:Yd49IBdFo0AJ:www.aou.org/committees/nacc/proposals/2010-A.pdf+N%26MA+Classification+Committee:+Proposals+2010-A&hl=en&gl=us&pid=bl&srcid=ADGEESiQx0NrFLMAaHiuZO1xsoZJA8jVBbR9tkyZKsf3lY-yVguig9hgn3k_daL3GJS9zXh3_1qyLAG0-6_SQnW5MOMeXOMZtpmoFJfMkJK0I5u4bXrRTAYKGi2mufhKbIpxQ4zMp6W7&sig=AHIEtbT4UG6CTa2FPSpfq8mjDUi9WRv26A

*

That's a huge Web site address to copy and paste, I know.....but it's worthwhile reading.

You'll learn the potential options for classifying Yellow-Rumped Warbler that the American Ornithological Union (AOU) committee is debating.

Meanwhile, where I live in the Bay Area (CA), it's common to see two subspecies in many habitats during the non-breeding season:

1. Myrtle Yellow-rumped Warbler (Dendroica coronata coronata)
2. Audubon's Yellow-rumped Warbler (Dendroica coronata auduboni)

Warbler Guy, which wood-warblers remain in the USA after the breeding season?

2011-01-08T07:14:00.005-08:00

Bridget, the answer to your question won’t take you long to read.

Among the breeding 52 North American wood-warblers, only a minority occur in the USA during the non-breeding season:
- Common Yellowthroat
- Black-throated Green
- Northern Parula
- Pine
- Orange-crowned (south Channel Islands, CA and along the California coast)
- Yellow-throated (southeast USA)
- Tropical Parula (in the extreme southern portion of Texas)
- Prairie (a subspecies in south Florida)
- Painted Redstart (southeast Arizona)

South of the USA, here’s some more North American wood-warblers that have non-migratory populations breeding as far north as Mexico:
- Belding’s Yellowthroat (Baja only)
- Bahama Yellowthroat
- Gray-crowned Yellowthroat
- Slate-Throated Redstart
- Crescent-Chested
- Fan-tailed Warbler
- Golden-crowned Warbler
- Rufous-capped Warbler

A few other species are reported rarely to irregularly after the breeding season in the USA, and, thus, could potentially be individuals that remain in the USA during a portion or throughout their brief lives, including:

- Tennessee
- American Redstart
- Nashville

Warbler Guy, what are the latest bird name changes (in the 51st AOU Checklist supplement)?

2010-12-17T15:39:00.004-08:00

Good question, Jeremy (one of my most frequent Warbler Guy inquirers).

Check out David Sibley's article about the latest American Ornithological Union-based common bird name changes at:

http://www.sibleyguides.com/2010/07/bird-name-changes-in-the-51st-aou-checklist-supplement/

At this link, you'll see name changes at both the genera (scientic name) and common name level for North American songbirds. For wood-warblers, only scientific name changes have occurred, principally in the genera Vermivora and Seirus (with the latter, after the changes, now containing ONLY one member: Ovenbird).

By the way, changes in the common names of birds is available for purchase at the AOU's web site where you can obtain the 51st Annual AOU Checklist Supplement.

Warbler Guy, how did so many kinds of wood-warblers evolve?

2010-12-12T09:53:00.001-08:00

Joe (in Kincaid, OR), I'll answer that excellent question more fully soon, but first let me point you to an
excellent related article in a birding blog:

http://dendroica.blogspot.com/2008/07/evolution-of-wood-warblers.html

Warbler Guy, are there any New World warblers that occur in their own family and where shall I look?

2010-11-19T15:30:00.002-08:00

The Olive Warbler, Peucedramus taeniatus , is a small passerine bird. It is the only member of the genus Peucedramus and the family Peucedramidae.

Breeding from southern Arizona through New Mexico and south into Mexico and Nicaragua, the Olive Warbler is the only member of the genus Peucedramus and the family Peucedramidae. All our other New World warblers are in the Parulidae family.

The Olive Warbler status in its one-member family is distinctive in that it's the only bird family endemic to North America (including Central America). Before it was classified into its current family, this warbler was considered a Parulidae, but DNA studies suggest that it split early in its evolutionary history from the other related passerines prior to the differentiation of the entire New World warbler/American sparrow/Icterid group.

Thus, bird taxonimists now place the Olive Warbler in a family of its own.

Like many other New World warblers, it is an insectivorous species of coniferous forests.

Though it is often said to be non-migratory, most New Mexican birds leave the state from November to late February. It lays 3–4 eggs in a tree nest.

FAB FIVE WARBLER QUIZ #3

2010-11-10T17:36:00.007-08:00

Can you identify the wood-warblers in each of the following five photos?

Warbler Guy, can you tell me some of the most abundant wood-warblers that were seen in last year’s Christmas Bird Count?

2010-11-03T17:19:00.002-07:00

Yes, Brent in Orange Co., CA, there’s a record of these results in the latest American Birds (110th CBC, Volume 64).

Consider the following highest totals and the corresponding location/name of the CBC:

- Olive Warbler, 9 (AZ, Green Valley-Madera Canyon)
- Tennessee Warbler, 2 (TX, Guadalupe River Delta-McFaddin Family Ranches)
- Oranged-crowned Warbler, 493 (TX, Weslaco)
- Nashville Warbler, 10 (TX, Weslaco)
- N. Parula, 18 (FL, Kendall Area)
- Yellow Warbler, 11 (CA, San Diego; FL, Coot Bay-Everglades N.P.)
- Chestnut-sided Warbler, 1 (AZ, Phoenix-Tres Rios)
- Magnolia Warbler, 3 (FL, Coot Bay-Everglades N.P.)
- Cape May Warbler, 1 (OH, Ragersville)
- Black-throated Blue Warbler, 2 (FL, Coot Bay-Everglades N.P.; Ft. Lauderdale; Kendall Area; and Key Largo-Plantation Key)
- Yellow-rumped (Audubon’s), 4,638 (CA, Orange Co.)
- Yellow-rumped (Myrtle), 7,599 (SC, Charleston)

Warbler Guy, did Kirtland’s Warbler nest in Wisconsin again this past breeding season?

2010-10-17T15:12:00.003-07:00

Wisconsin Kirtland's Warbler Nesting Update

Yes, Avery (in Chicago), the federally endangered Kirtland’s Warbler observations totaled a minimum of 24 male and 13 female individuals in the state. Among 16 nest sites monitored, three to five were successful, appearing to fledge an estimated 12 to 18 newborns.

Monitoring of nests or sightings of Kirtland’s Warbler (above photo) occurred in several Wisconsin counties — Adams, Marinette, Bayfield, Douglas, and Washburn. In Adams County, 20 male and 11 female Kirtland’s were documented. In turn, estimates of fledglings from these totals in 2010 ranged from 12 to 18 among three to five nests.

In Marinette County, a volunteer monitor found a single Kirtland’s at the same site where he documented nesting in 2009. Another single Kirtland’s male was also reported at another site in the county where birds were found in 2008 and 2009, and three males were documented at a third site.

In Bayfield County, a single Kirtland’s male was discovered on Bayfield County Forest land in early June and a follow-up visit yielded a second male plus a female.

In Douglas County, a single Kirtland’s was seen on the same date as the aforementioned Kirtland’s observed in Bayfield County. However, a follow-up visit by researchers failed to detect any presence of Kirtland’s so nesting could not be confirmed for 2010 here.

In Washburn County, a male Kirtland’s was observed, but a nest could not be found.

Interestingly, all 10 banded male Kirtland’s present in Adams County in 2009 returned in 2010, including one individual that had been originally banded in the Bahamas.

This year’s breeding results confirm that Kirtland’s Warbler has nested for four consecutive breeding seasons in Wisconsin. This sequence in unprecedented in the monitoring of this species that previous to 2007 was thought to primarily to exclusively nest only in 10 or so north-central Michigan counties. Given the now-annual breeding of Kirtland’s in Wisconsin, it’s safe to suggest the species now regularly nests in both states.

Warbler Guy, do the white tail spots in the Hooded Warbler (and other warbler species) provide it any benefit?

2010-09-27T14:11:00.003-07:00

Catrina (in Portland, OR), the answer is “yes,” if you agree with studies conducted by Dr. Ron Mumme. In the field, he tested his hypothesis that the Hooded Warbler’s (above photo courtesy of Dr. Mumme) contrasting white tail spots and tail-flicking behavior increase foraging performance by startling potential insect prey that the warblers then pursue and capture in flight.

Results of his experiment indicated that Hooded Warbler individuals with darkened tails had significantly lower prey attack rates and delivered significantly less food to nestlings than did birds with normal, unchanged tail feathers. He and other theorists continue to test their theory about the importance of contrasting tail pattern in helping birds capture prey, and, in doing so, note that all 12 species in the Myioborus redstarts (also known as whitestarts) display similar behavior while using their white outer tail feathers to also conduct foraging displays designed to startle and flush potential insect prey.

Warbler Guy, which warblers are superspecies?

2010-09-15T15:20:00.001-07:00

That’s a fine question, Jeremy (in Boise, ID).

Given a superspecies consists of two or more species that evolved recently into isolated breeding ranges next to each other, it is not surprising that superspecies’ members are closely related.

Among songbirds, think of Eastern and Western Meadowlarks. Their breeding ranges are separated across North America and are nearly isolated except for a small overlap area. The same kind of breeding isolation geography pattern occurs in more than 100 North American species that are considered members of 53 total superspecies.

Of these 53, some wood-warbler species qualify. Note the distinct breeding ranges of the Black-throated Green superspecies consisting of this species along with Black-throated Gray, Hermit, Townsend’s, and Golden-cheeked Warbler.

Other warbler superspecies include 1) Nashville, Virginia’s, and Colima; 2) Northern and Tropical Parula; 3) Yellow-throated and Grace’s; and 4) Mourning and MacGillivray’s.

Given, I saw your 9/2/10 article here, what warbler identification resources exist?

2010-09-07T20:42:00.002-07:00

Eddy in Chicago.......That's a good question.

Violating my own anti-shill policy, I'll suggest my own "Warbler Tips ID" chart (that is accessed at my web site's home page: www.warblerwatch.com)

This chart has a column that lists the look-alike species, in addition to mentioning 1) whether they are early to late spring arrivals/autumn departures during migration; 2) their conservation status; 3) other information.

The direct link to this warbler identification resource:

http://www.warblerwatch.com/warblertips.htm

Confusing Fall Warblers? Warbler Identification Tips?

2010-09-02T11:14:00.000-07:00

People often ask me to share the best ways to identify migrating warblers — especially in the East and Midwest where post-breeding plumages can sometimes create identification challenges.

My brief answer is that there’s no replacement for doing your homework in the field. Getting out early and often with your binoculars is the best way to see lots of warblers. The more challenging identification episodes you encounter, the faster you become precise with your warbler field skills.

One identification resource I recently found may interest you. It’s an online “chart” that’s found at: http://www.migrationresearch.org/mbo/id/fall_warblers.html

The author, Marcel Gahbauer, does a terrific job of separating 30 species of warblers by various key feather field marks: a) presence of wingbars or not; and b) facial, throat, and undertail characteristics.

Enjoy your late summer and autumn birding!

Warbler Guy, which wood-warblers use cavities for nests?

2010-08-18T11:37:00.003-07:00

Only two of our North American breeding wood-warblers use a cavity nest: Prothonotary (above photo) and Lucy’s.

Prothonotary nests usually occur in stumps and snags either standing in or near water. An old or abandoned woodpecker hole is typically employed, most often one previously occupied by a Downy Woodpecker or Black-capped/Carolina Chickadee. Nest heights range from 2 to 12 feet above ground or water, with an average of 5 feet in height. Prothonotaries occasionally nest in bird boxes and near buildings.

Lucy’s Warbler is the only cavity nesting warbler in the western USA. This species usually places its nest in four types of cavities: natural cavities in trees (usually mesquite) where the entrance is in a sheltered spot; under loose bark; in abandoned woodpecker holes (especially those of Gila Woodpecker (Melanerpes uropygialis) in saguaros [Carnegiea gigantean] or other trees); and in deserted Verdin (Auriparus flaviceps) nests. Lucy's Warbler occasionally nests in holes in banks, in soap tree yucca leaves (Yucca elata), elderberry (Sambucus mexicana), sycamore (Platanus spp.), or willow/

Lucy's Warbler rarely nests in burrows or depressions in river banks, rocky crevices, deserted thrasher (Toxostoma sp.) and Cliff Swallow (Hirundo pyrrhonota) nests, "pseudocavity" evacuated in mass of debris in tamarisk, or forks in small branches.

Warbler Guy, were any changes in warbler names recently applied?

2010-08-04T10:11:00.000-07:00

Yes, David (in Topeka, KS), the 51st supplement to the AOU Checklist of North American Birds includes changes to warblers names, but mostly due to the creation of new genera.

The new supplement includes the following changes:

• Blue-winged Warbler Vermivora cyanoptera
Formerly Vermivora pinus
• Tennessee Warbler Oreothlypis peregrina
Formerly Vermivora peregrina
• Orange-crowned Warbler Oreothlypis celata
Formerly Vermivora celata
• Nashville Warbler Oreothlypis ruﬁcapilla
Formerly Vermivora ruficapilla
• Virginia’s Warbler Oreothlypis virginiae
Formerly Vermivora virginiae
• Colima Warbler Oreothlypis crissalis
Formerly Vermivora crissalis
• Lucy’s Warbler Oreothlypis luciae
Formerly Vermivora luciae
• Northern Waterthrush Parkesia noveboracensis
Formerly Seiurus noveboracensis
• Louisiana Waterthrush Parkesia motacilla
Formerly Seiurus motacilla

Warbler Guy, which wood-warbler clutch has the largest number of eggs?

2010-07-24T10:04:00.002-07:00

Good question, Parker in New York City.

The answer is the Cape May Warbler (see female in photo, above), which usually lays six or seven eggs. Most other wood-warbler species typically lay four or five eggs in most instances. In extraordinary cases (that are seldom to rare), the Cape May deposits as many as nine eggs. In equally rare situations, merely four are laid.

Why does the Cape May lay eggs than other wood-warbler species? The answer may relate to the “boom and bust” cycle of its dominant food resource: spruce budworms (a larval form of a moth). When large population outbreaks of the spruce budworm occur, it behooves the Cape May to lay more eggs. Conversely, it makes sense that this species lays fewer eggs in years when spruce budworms are less plentiful.

Of course, this kind of phenomenon is not unique to Cape May Warbler. Many other bird species, in addition to other animals, act similarly in response to the presence or absence of food resources.

For more details about clutch sizes of North American breeding wood-warbler, see The Birder’s Handbook (Paul R. Ehrlich, David S. Dobkin, and Darryl Wheye)

Other life cycle information about USA-breeding wood-warbler species appears in a “Warbler Tips ID Chart” at my Web site: www.warblerwatch.com (After arriving at this site’s home page, click on the button title “Warbler Tips ID Chart.”

Warbler Guy, which vagrant warblers have recently been seen in Alaska?

2010-06-12T09:10:00.001-07:00

Good question, Thomas (in Cincinnati, OH).

According to the May, 2010 issue of Birding Magazine, the Willow Warbler (ABOVE PHOTO) (Gambell, St. Lawrence Island, 8/25/02), Sedge Warbler (9/3/07) and Pallas’s Leaf Warbler (9/25/06) are the three most recent significant observations.

(By the way, a vagrant bird is one that appears far outside its normal range. Some people believe “accidental” equates with vagrancy. Among a number of factors that cause a bird to become vagrant, genetics and weather conditions are two.)

Which warblers are predicted as upcoming potential vagrants to Alaska?

Candidates include Gray’s Warbler, Oriental Reed-Warbler, Black-browed Warbler, Pale-legged Leaf Warbler, Radde’s Warbler, and Japanese Bush-Warbler.

Warbler Guy, what are some good warbler identification resources?

2010-05-19T18:25:00.001-07:00

Andy (in Lacrosse, WI), I suggest you see:

http://www.giffbeaton.com/warblers.htm

http://birding.about.com/od/identifyingbirds/a/warbleridentification.htm

http://www.enature.com

http://www.warblerwatch.com/warblertips.htm

Warbler Guy, do migrating male wood-warblers arrive earlier than females to nesting grounds?

2010-05-11T17:27:00.003-07:00

(Above, a first-year male American Redstart is indicated by the slightly burnt-orange/amber outer tail feathers and forward flanks.)

Yes, Edward (in Cincinnati), multiple studies indicate males arrive earlier than females. One study (at Prince Edward Point, Ontario) even showed that the oldest adult American Redstarts arrived significantly earlier than second-year males of the same species. A similar trend was noted for approximately 20 other wood-warbler species.

Interestingly, species that spend the winter farthest north, arrive the earliest upon nesting grounds. That makes sense in the case of Yellow-Throated Warbler that arrive early in the spring in the Mid-Atlantic because they merely need to travel from as closeby as the southeastern USA where they spend the non-breeding season. This phenomenon supports the theory that males arrive early to take advantage of food resources and/or when climatic conditions are suitable, whereas females of the same species arrive when conditions are more ideal for successful nesting.

Later arriving species on their nesting grounds, including Blackpoll, travel from as far away as northern South America where they spend the non-breeding season. For this reason, during some spring seasons, it may not arrive on northern nesting grounds until June 1st and beyond.

Other wood-warbler species — Yellow-rumped and Pine Warbler, for example — that can subsist on berries and seeds, in addition to insects, are usually the earliest to arrive on nesting grounds. Among other early arriving species in the warbler march north include Palm, Black-and-white, Nashville, Wilson’s, Louisiana Waterthrush, Prothonotary, Northern Waterthrush, Wilson’s, and Yellow.

Warbler Guy, do all our returning eastern wood-warblers fly over the Gulf of Mexico during spring migration?

2010-04-27T10:42:00.003-07:00

(Nashville Warbler, above. Note it’s often difficult to see its light brown-orange cap, though its prominent eye-ring and absence of wingbars are good field marks.)

“No,”(Byron in Laramie, WY) is the quick answer.

Although the majority of East Coast and Midwest breeding wood-warblers fly over the Gulf upon returning to the USA, there’s at least three that fly around the Gulf:
Nashville, Mourning, and Canada.

That is to say, these three “Circum-Gulf” migrating species use an overland route by arriving in the USA via Mexico.

The non-breeding season range of the Nashville Warbler is primarily in Mexico, so they have the least amount of miles to travel as migrators. Moving north in spring, they typically always arrive earlier than Mourning and Canada in northern Midwest and Eastern latitudes. In fact, among the 30 or so wood-warblers that birders observe annually in northern latitudes, Nashville may be considered an early arrival among the vanguard. Some of the Mexican wintering Nashville travel to the West Coast for breeding and are considered a different subspecies.

Canada and Mourning, on the other hand, are known as later arrivals in the warbler migration parade. Canada comes all the way from southern Central American and northern South America, so it makes sense that its route through Mexico takes longer than many other warbler species.

Patient birders often have to wait even longer into May to see Mourning. That’s because it winters almost exclusively in northern South America. Winging north requires Mourning to travel more miles than most arriving Nashville and Canada populations. As a result, Mourning usually doesn’t appear in its breeding territory until mid-May, often later in some spring seasons.

If, for example, cold weather occurs throughout much of May and northerly breezes prevail, then Mourning may not arrive until late May in portions of its northern nesting areas. Only Blackpoll is known to arrive later during these inclement seasons when many other warbler species may also arrive later than usual.

Warbler Guy, what are the answers to the most recent quizzes on your blog’s right column? (Jeremy K., Seattle, WA)

2010-04-14T21:16:00.001-07:00

Here’s the answers, Jeremy, with corresponding date (if applicable) for each quiz provided as you scroll down from today’s date and backward in time:

1. March 2 Photo Quiz:

Photos from top to bottom = MacGillivray's, Connecticutt, Chestnut-Sided, Lucy's, Hermit

2. Which wood-warbler is typically the earliest long-traveling migrant back on the East Coast? West Coast?

Answer: Louisiana (remember, it said “long-traveling” migrant); Orange-crowned

3. March 1, 2010 article and corresponding quiz:

Which wood-warbler species has gained the most population by percentage in the last 20 years?

Answer: Kirtland’s, as the population increased to nearly 1,400 singing males by the mid-2000s after hovering around 200 males through the mid-80s.

4. January 10 Photo Quiz:

Photos from top to bottom = Aud.'s) Yellow-Rumped, Wilson's, Bl.-Thr. Blue, Blackpoll, Hermit

5. Approximately how many miles are trans-oceanic migrating Blackpoll (Warbler) traveling if they begin in New England and arrive in northern S. America (For help, see the 9/29/09 article)?

Answer: 2,150 one-way (for example, Blackpolls leaving New England travel as far as this distance to northern South America where they spend the non-breeding season.

6. Pretend you're attending an upcoming Christmas Bird Count (CBC) in any of the lower 48 states. Which two wood-warbler species are the most likely ones MOST people would see?

Answer: In most cases and during most years, it’s Yellow-Rumped and Common Yellowthroat (though Palm can sometimes persist and/or over-winter in some northern latitudes).

7. Can you name two wood-warbler species that are breeding endemics to one USA state?

Answer: Golden-cheeked (a true endemic that breeds only in Texas) and Tropical Parula, though the later breeds farther south outside Texas.

Warbler Guy, which warblers look alike? Which are the most confusing warblers to identify from each other?

2010-03-28T22:11:00.006-07:00

Thanks, Gilman (in Paso Verde, CA)

Right, which photo is the Orange-crowned? Tennessee?

Warbler identification challenges are ALWAYS the leading questions I get in the spring.

So here's ten typical “double-take” ID challenges you’re likely to encounter when the going gets tough on the boardwalk as the warbler march begins:

(i.e., Knowing the breeding ranges and which habitats the following species tend to frequent and/or nest within is always helpful in identifying look-alikes from each other – among other factors.)

1. Chestnut Sided and Golden-Winged

2. Magnolia and immature Prairie

3. Black-throated Green and Townsend’s/Hermit hybrids

4. Yellow-throated and Grace’s

5. Kirtland’s and Palm (and Prairie)

6. Yellow-Rumped (Audubon’s subspecies vs. Myrtle subspecies) (and intergrades of Audubon’s and Myrtle occur in portions of British Columbia and Alberta)

7. Tennessee and Orange-Crowned

8. Ovenbird and Northern Waterthrush (or Louisiana Waterthrush (they are all in the same genus)

9. Connecticutt and Mourning

10. Mourning and MacGillivray’s

Warbler Watch (Indeed): Daniel's Upcoming Birding Forays

2010-03-20T21:01:00.005-07:00

If you're in the Bay Area/California, then maybe you'll appreciate noting my upcoming birding outings:

*

Upcoming Birding Field Trips
with Daniel Edelstein (www.warblerwatch.com)

(Birding Instructor @ Merritt College, Birding Guide
& Wildlife Biologist; edelstein@earthlink.net)

Low Cost: $25 per full day field trip
($20 per day if you register for four or more field trips)

Visit the best birding sites in the Bay Area & Sierras (@ peak of breeding/song)

Daniel’s 25+ years of ornithology/biology experience,
plus handouts you’ll receive (and use of his A-1, 25x-50x zoom scope & binoculars)

1. Bay Area (i.e., to prime-time songbird (“Birding By Ear”) hot-spots)
- April 17th, Mitchell Canyon, Mt. Diablo State Park, Walnut Creek,
9 am – 3 pm
- April 31st, Mines Road/Del Puerto Canyon, Livermore area,
9 am – 3 pm
- May 8th, Point Reyes National Seashore, Bear Valley
9 am – 3 pm

2. Sierras (i.e., we’ll visit optimum breeding areas for common & rare birds)
- June 5-6, Yuba Pass/Gold Lakes area (Sardine Lake, Sand Pond, etc.)
- June 12-13 Sierra Valley (Marble Hot Springs Rd., Dyson Lane, Loyalton area)

Cost: $25 per day’s outing or any five days for $100 (Minimum of eight people needed to ensure each day’s field trip is a “go.”)

Directions/Etc.: If you respond with a “yes” to one or more of the above dates, I’ll send you precise directions/maps/motel-camping options, details/etc.

Email questions to Daniel (an Adjunct Merritt College instructor in its Biology Dept.): Edelstein@earthlink.net

Learn about Daniel’s 25+ years of birding experience and print FREE Bay Area/ California birding information at: www.warblerwatch.com &, in addition, please note Daniel’s popular “Wood-Warbler” blog site: http://warblerwatch.blogspot.com

FAB FIVE WARBLER QUIZ #2

2010-03-02T20:05:00.006-08:00

Can you identify the wood-warblers in each of the following five photos?

Warbler Guy: Do any wood-warblers use cavities for nesting?

2010-02-13T14:30:00.011-08:00

Lynnette in Elm Grove, WI asks an interesting question.

Jeanne Marie Acceturo is our guest writer who has ALL the answers for you:

One hundred fourteen wood-warbler species nest in the Americas and Bahama Islands. But only two of them use cavities for nesting: the Prothonotary Warbler (Protonotaria citrea) (PRWA, bottom photo) and Lucy's Warbler (Vermivora luciae) (LUWA, top photo).

Newly returning males of both species will soon arrive after migrating. They’ll define and defend territories before females arrive a week or two later (in April for the bulk of most breeding sites in the United States).

Males do all the wooing. Females make all the choices. Her big decisions: Which male has excellent taste in real estate? What constitutes a million dollar listing in the wood-warbler world?

Unlike PRWA and LUWA, other wood-warbler species prefer nesting sites within dense shrubs, atop a tree branch, or in a nook under a tangle of ground cover. Our two cavity nesting wood-warblers prefer otherwise, instead often utilizing dead snags or live trees where standing water provides a moat directly below the nest site.

Last year’s Downy Woodpecker hole? To a PRWA, it’s the perfect choice. Bald cypress, willow and sweet gum are the typical host trees. Male PRWAs make a platform of moss inside each suitable cavity in their territory. The females construct the nest and include mosses and liverworts.

Why? Perhaps it’s because damp nesting material increases humidity inside the cavity so that eggs are less likely to dry out.

But that still doesn’t explain why PRWAs use cavities. The mystery remains. One theory relates to the added protection obtained from living inside a limb hidden from predators such as marauding rat snakes.

In an all-too-familiar story, however, much of their preferred bottomland hardwood forest is disappearing. People have destroyed 90 percent of this habitat for logging, agriculture and other development. Fortunately, there’s good news: PRWAs sometimes use nest boxes when they’re erected in suitable locations.

Lucy's Warbler, the West Coast first cousin of the more East Coast based PRWA, also nests near water. But where’s a LUWA likely to find water within the lower Sonoran desert habitat that it favors? Not too many places. So LUWA changes its game plan: old Gila Woodpecker holes or abandoned Verdin nests sometimes become Home Sweet Home. So do crevices behind loose tree bark, natural cavities, or, less commonly, spaces among large networks of loosely tangled roots in riverbanks.

Populations of LUWAs have dropped for an obvious reason: the Southwest has been developed intensely. Unfortunately, LUWA rejects nest boxes, but where LUWA’s natural habitat of mesquite forest has been lost to logging and water diversion, introduced (and invasive) tamarisk trees pinch hit as substitute nesting sites.

Are either PRWA or LUWA listed as threatened or endangered? Not yet, but conservation of these two species’ remaining populations presents a cautionarytale — one that depends on habitat conservation as a rule and not an option.

Lucy's Warbler Photo: © Dominic Sherony; Prothonotary Warbler Photo: © Mdf

Warbler Guy, Help Me?: I’m in Florida and wondering if the photos here are western or eastern subspecies of Palm Warbler?

2010-02-07T07:36:00.007-08:00

Thanks for the question, Mr. King. (Both photos courtesy of an excellent birder, Jim McGinity.)

Your photos are both “Western” Palm Warbler, despite your East Coast location.

That’s because during the “winter,” it’s possible to see both the subspecies that occur within the Palm Warbler species.

More details follow:

Telling both subspecies apart in the winter/non-breeding season may and can be challenging. Underline the last sentence (!)

To wit: Although you can see both subspecies during the non-breeding season/winter in Florida, the pale “Western” subspecies (Dendroica palmarum palmarum) often adds a touch more of yellow under its belly during the fall (through winter).
For this reason, some population members of “Western” may look like the “Yellow” (East Coast” subspecies, D. p. chrysolepis. The latter (the “Yellow” East Coast version) is much brighter during the breeding season than the “Western” Palm Warbler subspecies.

Got all that?

If not, here's a MAJOR tip.....

It’s an excellent field mark that helps you tell the two subspecies apart:
the yellow eye-ring that’s shown in the “Yellow” Palm Warbler (D. p. chrysolepis).
In contrast, the “Western” Palm has a WHITE eye-ring.

Even more details about the two subspecies yellow color follows:
“Western” yellow has a contrasting pattern where the yellow ends and the rump is a duller green (but more yellow in the “Yellow” East Coast subspecies (D. p. chrysolepis).

Note there are intergrades and, indeed, a potential breeding area in Canada where both subspecies may successfully mate with each other and have viable offspring.

Despite all the details I’ve already present, this account oversimplifies how to identify both subspecies from one another. Excellent drawings of both subspecies appear in “A Field Guide to the Warblers of North America” (Jon Dunn and Kimball Garrett) (plate #20, page 82). More details about how to tell them apart are described on p. 366 in this book.

The plates are “Must See” viewing for warbler fans like you, Mr. King, but I hope the account above answers your question.

If not, please ask me more questions.

That’s why I’m here as “The Warbler Guy.”

Population Explosion?: Kirtland's Warbler Responds To Wildlife/Habitat Management

2010-02-01T20:45:00.005-08:00

See the current quiz on the right side?

Now look at the above graphic that shows the annual population changes of Kirtland's Warbler in Michigan during the last 20 years.

Hmmmm.......Do you think the current majority of folks who answered the quiz are correct? Incorrect?

Truth be told, the Michigan DNR's habitat management plan is a huge victory for the federally endangered Kirtland's.
Their populations in 12 central-northcentral Michigan counties continue to thrive. Prescribed fires have helped create optimum conditions in their Jack Pine community whereby managers have helped Kirtland's rebound from the brink of extinction in the late 1980s.

For more information, see:

http://www.michigan.gov/dnr/0,1607,7-153-10370_12145_12202-32591--,00.html#quickfacts

Of course, Wisconsin breeding populations of Kirtland's are also big news. During the past three breeding seasons, Wisconsin has hosted newborns in at least two counties. For more details about the discovery of Kirtland's Warbler in Wisconsin and an overview of their breeding abundance, see one or more of my June and July, 2009 updates/articles in the archives section of this wood-warbler blog.

Warbler Guy, Where may I most likely see warblers in northern California near you (or where might I see warblers in Marin County)?

2010-01-17T09:03:00.010-08:00

Thanks for asking, Jeremy (in Mill Valley, CA).

Here's a great web site to note seven fine Marin County birdwatching spots (i.e., the best birding places in Marin County, and, arguably, some of the finest birding locales in northern California):
http://www.marintrails.com/birds.html

(By the way, my Web site, www.warblerwatch.com, features a button -- "2010 Nature Watch Calendar" -- where you can read several brief accounts that discuss wood-warblers in northern California and, in particular, wood-warblers in Marin County.)

Currently, among the seven on the list, I suggest going to Rock Springs (on Mt. Tamalpais) and
Muddy Hollow (within Point Reyes National Seashore, a paramount, iconic place on the W. Coast to see diverse species of birds in multiple families/orders).

In these two spots where forests occur, the most likely wood-warblers to see currently include TOWNSEND'S WARBLER (non-breeding season resident only; see closest above photo) and YELLOW-RUMPED WARBLER (typically the AUDUBON's subspecies).

At Rock Springs and Muddy Hollow, watch for the much less common (in this order) ORANGE-CROWNED and HERMIT WARBLER, too -- though they are both rare to absent throughout most of Marin Co. during January (Populations of these two neotropical migrants return in late winter and spring, thereby nesting in suitable habitats throughout the County.) Even more rare at this time of year is to see the NASHVILLE WARBLER (above photo, below the headline), though it periodically makes a cameo appearance and, indeed, the local annual Christmas Bird Count surveyors such as Rich Stallcup sometimes extract one from the landscape.

#2: Fab Five Warbler Quiz

2010-01-10T20:29:00.007-08:00

Can you ID the five wood-warblers in the photos? (Answers will be here by 1/20/10; please check back)

Please see the nearby quiz where you can select your answers.

{As promised, here's the answers to the 12/27/09 quiz, below (from top to bottom):
- BLACK-THROATED GRAY
- YELLOW-BREASTED CHAT
- TOWNSEND'S
- KIRTLAND'S (HATCH YEAR INDIVIDUAL)
- KIRTLAND'S (MALE) }

#1: WOOD-WARBLER Photo Quiz (Quiz Yourself, If You Please)

2009-12-27T07:52:00.012-08:00

Can you identify the wood-warbler species in the five (5) photos, above?

(Hint: There only four total species among the five photos.)

Answers will be posted here in my next article that will appear no later than 1/5/10. Please check back, in addition to noting my NEW 2010 "Daniel's Nature Watch Calendar/Phenology Calendar" that will be posted at my regular web site by the first week of 1/2010:

http://www.warblerwatch.com

Happy New Year, Daniel
edelstein@earthlink.net
415-382-1827

(Photo credits from top to bottom: Kevin Stockman, Martin Meyers, Martin Meyers, WI DNR, and WI DNR)

Warbler Guy, have wood-warblers shifted their winter distribution as warmer winter temperatures have become more common in recent years?

2009-12-12T06:35:00.004-08:00

(Above, thanks to Martin Meyers for submitting a Common Yellowthroat male photo (taken in Nevada) )

That’s a fine question, Howie (in Minneapolis).

Turns out the answer is “yes,” if you agree with a recent technical report titled “Birds and Climate Technical Report (Niven, Bucher, and Bancroft, 2009; birdsandclimate.Audubon.org)

This report tracked the locations of 305 species by using Audubon Christmas Bird Count (CBC) data collected in the past 40 years throughout the lower 48 states (and s. Alaska and s. Canada).

Among these species, researchers suggest 58% of them shifted farther north in the past 40 years. They include many non-warblers such as Fox Sparrow, Pileated Woodpecker, Pine Siskin, Purple Finch, Ring-Billed Gull, and Fox Sparrow, among others.

Which wood-warbler species has shifted father northward during winter? It’s the Common Yellowthroat. Seeing this moisture-centric species on CBCs is not uncommon during the breeding season, especially because they are found throughout all of the lower 48 continental states. In addition, even seeing them throughout the winter in southern states is regular occurrence.

More eyebrow-raising: Seeing them increase their presence in northern USA states when the December/January CBC surveys occur. By this time, insect resources should have ebbed. Resources are few and far between. The pantry is empty for most insect-dependent bird species, such as Yellowthroats.

In other words, a sighting of a Common Yellowthroat on an Illinois or Indiana (or Wisconsin) CBC used to be much more rare. But the current report suggests the shift northward has made a winter-time Yellowthroat observation less rare.

The authors of the report cite four lines of evidence as verification of warming climate being a major factor in why bird species’ (including the Yellowthroat’s) have shifted north during the last 40 winters.

Time and space doesn’t allow me to discuss these four areas. But it’s worth noting that the birds’ movement north is consistent with computer model predictions based on a hypothesis of global warming/climate-change effects, according to the authors’ contention.

To read more about this report, see: www.birdsandclimate.audubon.org

Warbler Guy: We've missed you since your 11/7 post? What's up? When will you return? Inquiring warbler fans wish to know (!)

2009-11-22T06:20:00.002-08:00

OK, OK, I'm guilty as charged.

My college class that I'm teaching ("Ornithology") has been my child to babysit for lately -- and I'm not complaining.

The field trips are fun as a complement to the Powerpoint slide shows I present during class (Merritt College).

BUT I'm on my next article that you'll soon see here:

How the Old World warblers (the Sylvids) have been split and re-organized.

It's an interesting development.

Yet it also requires a reading length almost equal to scanning every name in the NY City phone book.

In other words, it's a time drag and, tongue in cheek intended, a near Master's Degree in descriptive research to learn about the Old World Warbler taxonomy changes.

I'll be back at you soon.....and, meanwhile, enjoy the birding and our wood-warbler friends.

Regards, Daniel

Warbler Guy, which warblers are the most common to see at the upcoming Christmas Bird Count (CBC) events?

2009-11-07T02:11:00.008-08:00

Oh, “yes,” Floyd D. in Davenport, IA. . . Wood-warblers are often detected in non-warm weather areas where the 2009-2010 CBC events will soon happen. (Given Floyd also wonders if "seeing warblers during a northern USA CBC is even possible?" I'll answer that phase, too, below.)

Before I mention the highest wood-warbler species totals for the most recent (2008) CBCs, consider how cold weather-challenged states such as Minnesota, Wisconsin, Michigan, New York, and others routinely report Yellow-Rumped Warbler for selected CBCs.

As you may already know, upon moving south from the aforementioned states, it’s increasingly likely that your CBC experience will include sightings of winter-challenged-weather songbirds such as wood-warblers.

As a result, CBCs occurring in, for example, southeastern USA states typically document more total Yellow-Rumped individuals (i.e, Yellow-Rumped Warbler may and can be found annually during CBC viewing periods (mid-Dec.-early Jan.) in almost every eastern state east of the Mississipi River except for Minnesota and some to many New England states.

Other COMMONLY detected wood-warbler species seen during CBCs include Orange-Crowned, Yellow-Breasted Chat, Palm, Northern Waterthrush, Northern Parula, Yellow-Throated, Black-and-White, and Ovenbird.

Now, Warbler Guy presents a strange brew of wood-warbler totals from the 2008 CBC season and for various North American “Tally Rally” totals:

- 17 Painted Redstart (Arizona’s Green Valley-Madera Canyon CBC);
- 15 American Redstart (Florida’s Coot Bay-Everglades CBC);
- 70 Black-and-White (Florida’s Coot Bay-Everglades)
- 524 Common Yellowthroat (Texas’ Guadulupe River Delta-McFaddin Family Ranches CBC)
- 17 Wilson’s Warbler at the coastal Orange Co., CA CBC

Three Brief Warbler Questions......(BELOW)

2009-11-02T22:14:00.004-08:00

(Drawing of Bachman's Warbler, left*)

(* = My monologue and one-liners about Bachman's Warbler and other topics follow.)

Here’s three brief questions that I’ve received recently. My humble apologies, but I’m hyper-uber busy with deadlines this week for field survey/biological work and teaching (i.e., I’m preparing to teach an Ornithology class at Merritt College that begins soon), so I’ve got a monologue of “one-liners” for answers, below.

1. Warbler Guy: How many wood-warbler (Parulidae Family) members are there within the A.O.U. checklist area (A.O.U = American Ornithological Union)?

Answer: 78 species, including some of the coolest names that even the best namers of cars would likely not have the ingenuity to produce: Fan-tailed Warbler, Buff-rumped Warbler, and Elfin-woods Warbler.

2. Why is Bachman’s Warbler still featured in some field guides (see nearby drawing)?

Answer: I don’t know and I remain puzzled – given that the most recent specimen was collected in 1949 in Mississippi and the last probable breeding pair was seen that same year in South Carolina. Note the last confirmed sightings were near Charleston, South Carolina from 1958 to 1961.

Therefore, if you wish to enliven a boring dinner cocktail party's conversation, then speak louder than normal while mentioning your sighting of this wood-warbler....(smile).

3. Warbler Guy, I know the “Old World” warblers are classified into the family Sylviidae, a different one (among 228 worldwide) than the “New World” wood-warblers family (Parulidae). Given the Sylviidae members primarily occur in a different hemisphere (e.g., where Europe is located), do some ALSO live in the “New World” (North, Central, South America)?

Answer: Yes, the A.O.U. checklist area (see #1 question, above)
includes 12 species, with your best chance for viewing a Sylvid member in Alaska during the summer when the Arctic Warbler is present (Note: A vagrant sighting of Dusky Warbler, a Sylviidae family member, occurred recently in the Santa Cruz, CA area.

Otherwise, good luck finding "Old World" warblers in the lower 48.

No worries, however. Most of our 114 or so wood-warblers in the Americas are prettier than their Old World classmates. We got lucky on the avian spin of the dice there. To wit, you don't hear about too many birders going to see warblers in Europe, correct? On the other hand, wood-warbler watching in the USA is peaking with the piqued interest of millions. Go to Point Pelee or Magee Marsh in the Midwest during the initial two weeks of May and you'll get my drift.

Hey, Mr. Warbler Guy: Is a Yellow-Breasted Chat truly a wood-warbler? C’mon, they don’t look like one, act like one, or sound like one.

2009-10-21T22:47:00.005-07:00

Answer: Good question, Rob, in Cordelia, CA.

At seven inches from bill tip to tail tip, the Yellow-Breasted Chat (YBCH) is EASILY our largest North American wood-warbler family member. All the other warblers in our area range from 4.25 to 5.5 inches in length. Equally vexing, unlike YBCH, most other wood-warblers have an insect-catching small bill. Consequently, seeing a YBCH’s oversized one — it looks more like a tanager’s in shape and size — leaves you scratching your head.

So does hearing its Northern Mockingbird/Brown Thrasher-like song. Even the YBCH’s skulking, secretive behavior is somewhat strange for a wood-warbler, given many (especially among the 27 Dendroica genus members in North America north of Mexico) are extroverts in fast-forward mode during the breeding season while displaying “hover and glean” foraging behavior in search of insects amidst the tips of branches.

So why is a YBCH considered a wood-warbler? Primarily because researchers use more than birds’ songs, their behavior, their skeletal structure, and their general appearance to define a species (as well as the genera, families and orders of birds that constitute the 9,800 or so species in the world). They also employ blood analysis (i.e., DNA/DNA hybridization techniques) techniques. All of these aforementioned distinguishing techniques form the “Phylogenetic Species Concept” that is broadly accepted by most taxonomical scientists (but only SOME biologists) as an accurate way to determine a species.

Of course, molecular analysis of blood is a somewhat recent development technique for distinguishing birds at the species level. Hearken to pre-DNA analysis, and you stumble upon the studies of one E. Eisenmann. In1962, he called into question the then generally accepted placement of the YBCH in the wood-warblers by pointing out how it is missing jaw muscle, thereby suggesting an affinity with tanagers (Thraupidae family). Eisenmann also argued that the YBCH’s hyoid apparatus (a specialized system of bones and muscles within the avian tongue) differs from that of design present in many songbirds. No matter. Eisenmann lost his tug of war with other experts. Various conscientious objectors in the birding community have similarly raised their voice (and ire) to question the inclusion of YBCH in the wood-warbler family.

Adding fuel to the debate is the American Ornithological Union's checklist of birds where an you an asterisk appears after YBCH's name, denoting that this species is "probably misplaced in the current phylogenetic listing, but data indicating proper placement are not yet available" (see http://www.aou.org/checklist/north/full.php).

Nonetheless, YBCH holds tight. It officially remains a wood-warbler.

Stay tuned.

Warbler Guy: What does Myrtle vs. Audubon's Warbler mean? Are not they both Yellow-Rumped Warbler?

2009-10-10T23:36:00.017-07:00

Thanks, Jill in Ocala, Fl.......No worries, Jill —
as even the experts have trouble figuring out how Audubon's and Myrtle fit into the systematic scheme by which Yellow-Rumped Warbler occurs in the majority of states, including Alaska.

Living in a vast range that stretches from our 49th state to Guatemala, consider how this common to abundant species has confounded taxonomic researchers over the years. In turn, it's not surprising that some birders are, likewise, challenged as to what to call a Yellow-Rumped when they see it. Myrtle? Audubon’s? Hooveri? Intergrade (i.e., Hybrid)? — if you’re in Alberta or British Columbia during the breeding season and note a Yellow-Rumped that shares field marks of both Myrtle and Audubon's).

So, given space limitations here, and based on the need to oversimplify the reasons for the split of this species into subspecies (and what a subspecies means in terms of its definition), here’s the current organizatonal "flow-chart" that the experts (e.g., citing approval from the American Ornithological Union that is the ultimate soothsayer in deciding this bird's classification nomenclature) have established for the Yellow-Rumped Warbler:

Five subspecies occur in the Yellow-Rumped Warbler species:

MYRTLE YELLOW-RUMPED GROUP = 2 subspecies:

1) Dendroica coronata coronata = Myrtle (Yellow-Rumped) Warbler; 2) D.c. hooveri = Hoover's (Yellow-Rumped) Warbler (not recognized by Jon Dunn and Kimball Garrett's 1997 "Warbler" Field Guide, but this subspecies is acknowledged within the Birds of North American Online). (See http://bna.birds.cornell.edu/bna/species/376/articles/systematics if you have a subscription to this $40 per year service; if you need to join, please go to
http://bna.birds.cornell.edu)

AUDUBON'S YELLOW-RUMPED GROUP = 3 subspecies:
(#3-#5 among the five subspecies in the species)

3) D.c. auduboni = Audubon's (Yellow-Rumped) Warbler;
4) D.c. nigrifrons = Northwest Mexican Black-fronted (Yellow-Rumped) Warbler) (non-migratory); and
5) D.c. goldmani = Guatemalan Goldman's (Yellow-Rumped Warbler) (non-migratory).

Such an update in the taxonomy of Yellow-Rumped means
my earlier post from 2009 on this “wood-warbler” blog is now outdated.

Previously, Jon Dunn & Kimball Garrett split Yellow-Rumped into six subspecies: two subpecies formed the Myrtle Yellow-Rumped Warbler and four subspecies living in different geographical areas qualified within the Audubon's group.

Got all that? Your eyes are plowing through the snow drifts of words, above, but have not yet resorted to wearing snow tires?

If so, then consider one final thought related to Yellow-Rumps:

It's the word "impressive" -- as in suggesting this term is even too modest a way to describe the Yellow-Rump’s amazing BraveHeart survival ability, given its presence throughout the winter during many years within higher latitudes (i.e., upper Midwest and southern New England) where chilly winters prevail.

On the other hand, where I live in the mild Bay Area of northern California, the over-wintering bar is not as high for Yellow-Rumps whose presence during the non-breeding season includes both visiting populations of Audubon's and Myrtle's. Here, they are a common to abundant sight amid various habitats, including Eucalyptus, Monterey Cypress, and Monterey Pine groves within urban, suburban, and rural habitats.

Talented, refined “birding by ear” listeners are able to determine the Myrtle vs. Audubon's subspecies by each's diagnostic, yet sound-alike call note — a challenging feat, to say the least. In fact, I opine that the difficulty of distinguishing the two subspecies from one another by call is for many birders on par with identifying by sight a week-old Twinkie from one that has aged for two weeks. Not too easy, correct? Notice that I’m mentioning “call note” here because the songs of Myrtle vs. Audubon's are indistinguishable, according to Dunn & Garrett.

As for the multiple drawings devoted to this species on the color plates featured in Dunn and Garrett's Warbler field guide (as drawn by the fine artist and birder Tom Schultz), it exhibits excellent views of the diagnostic field marks germane to each subspecies.

In short, to tell them apart, note how Myrtle is the only subspecies of the four adults to exhibit white in the throat compared to the faint to brilliant yellow sheen seen in the other three subspecies: Audubon's, Black-fronted, and Goldman's.

Warbler Guy: Do warblers migrate over the ocean or was this bird (below photo) confused and lost?

2009-09-29T04:57:00.007-07:00

Thanks for the question, Kevin.

Here's my answer, though it's a simplified one to your question that deserves more ink than this digital retorte provides.

*

Given your interesting photo of the Black-Throated Gray Warbler that landed on your boat’s deck while amid the Pacific Ocean, it’s 100% certain that your unfortunate friend is lost and wayward from its normal southern migration route. More exact, no wood-warbler species on the West Coast have yet been discovered to migrate to non-breeding/wintering grounds via an oceanic route.

On the West Coast, only disoriented and/or wind blown wood-warblers show up on offshore islands, such as those often seen by bird banders/researchers stationed at the central California chain of islands called the Farallones. Here, banders have captured in their nets various species of so-called eastern wood-warblers. Others, like the Black-Throated Gray in the photo, below, are wayward sojourners desperate for a wayside to rest upon while fighting to survive in a pelagic habitat that offers no food resources.

Unfortunately, the vast majority of wood-warblers seen resting on boat decks, buoys, and rip-rap along coastal and deep water habitats typically are hatch year birds. Most will either perish while traveling over the Pacific ocean before reaching island refugia such as the Farallones or incur high mortality after being set free by banders that discover them. Some researchers suggest eastern wood-warblers found on the West Coast (including Farallone Island individuals") are inherently "dyslexic" in the sense they do not have the orientation design necessary to complete the classic migration routes that their brethren successfully negotiate each spring and autumn on their north and south peregrinations.

Beyond the West Coast, trans-oceanic migration by songbirds is rare -- and, in the wood-warblers seen in N. America north of Mexico, it is only documented to occur in a few species.

One of them, for example, the Blackpoll is known to contain populations that in autumn perform the high-octane feat of an ocean migration route that totals more than 2,150 miles (NE USA/Maritime Provinces to northern South America).

How do researchers know the Blackpoll performs such a magician's stunt annually?

It's because bird bander's in Bermuda (an island east-southeast of the southeastern USA) band birds in the autumn, and, thereby, sometimes catch Blackpoll in their nets. Evidently, Bermuda is in line with the route over which Blackpoll travel during their southbound migration and this small island serves as a stopover wayside area for Blackpoll that wish to stop and "refuel" before leaving to migrate south again at night.

High-octane is an apt description of the Blackpoll's Herculean task because many leave their "staging" grounds en masse with other Blackpolls and fly en route together as heavyweight butterballs while weighing as much as 26 grams (nearly an ounce) at the beginning of their air treks.

By the end of the Blackpolls' long-distance trip, however, they have been documented to have lost half their starting weights. Emaciated and Twiggy-Thin Blackpoll, therefore, in some cases, are known to digest their muscle to serve as a last resort energy source.

While winging south, researchers have figured Blackpolls burn .08 grams per hour during their three to four days of travel, a process that is a non-stop direct flight, if the Blackpoll does not stop at island refugia such as Bermuda. In comparison, such a weight loss program for club members and gym rats on two legs would mean a 20-pound or more evaporation of girth per day (for the typical weight of 6' tall male or 5'6" female).

Now there's a weight loss program that would attract headlines and lead to a manic panic for (I imagine) a best-selling book titled: "Migrating With a TailWind To A Fat-Free Lifestyle." :-)

Warbler Guy: To help me with my warbler identification skills, can you tell me which warblers look the same year-round and don’t seem to become drab?

2009-09-18T05:28:00.002-07:00

Among the 52 wood-warbler species typically seen annually in North America (north of Mexico), only 11 wear their flashy, bright, high-definition (alternate) plumage year-round. The vast majority — the other 41 species — undergo a molt before they migrate, so the males turn drab and less colorful after the breeding season.

Which11 warbler species look similar year-round?:
According to two sources I carefully checked — “Field Guide to Warblers,” (Jon Dunn & Kimball Garrett) and “Identification Guide to North American Birds (Part 1)” (Peter Pyle) — the answer is Golden-Winged, Yellow-Throated, Pine, Prothonotary, Worm-Eating, Swainson’s, Ovenbird, Louisiana Waterthrush, Red-Faced, Painted, and Yellow-Breasted Chat.

Expanding upon the basic facts presented above, most North American birds replace all their feathers during a complete molt that occurs in late summer or fall. The new feathers that develop before the birds leave on migration create an appearance that will be present throughout the fall and into winter. The technical word for this appearance is “basic plumage” because it usually persists longer throughout the year than the breeding (or alternate) plumage stage.

As indicated above, the majority of wood-warblers undergo a second molt that may occur progressively throughout the winter on the non-breeding grounds or as a more rapid molt before they leave to migrate north. This molt is called the peralternate molt and results in alternate plumage (or breeding plumage). In simple terms, think of this molt as providing birds the ability to “alter” their appearance to be colorfully attractive for the breeding season.

Of course, it is the males that most benefit from shedding their basic, non-breeding, drab (basic) plumage and transform into a brighter façade. That’s because the females pick their male partners when nesting occurs on the breeding grounds, a process that begins after migrating males arrive and preceded by the prealternate molt that occurred for them in their non-breeding grounds.

If you’re lucky enough to see warblers performing breeding and courtship displays, then you’ll see first-hand how the pretty males attempt to catch the eye of their female suitors (that are typically slightly more drab in appearance). Courtship poses include various wing gyrations and diving/hovering displays, among other behaviors.

As a closing note, it’s a good idea to remember that not all prealternate molts result in a prettier, more colorful appearance among male birds. Consider three ptarmigan species in the western USA and Alaska that molt from a majestic snow white basic plumage appearance to a more mottled, camouflaged expression that matches their tundra (and other habitat) surroundings and is, thus, more suitable for the ptarmigans’ survival in their summer environs.

Wisconsin Kirtland's Warbler Nesting Update

2009-09-03T04:30:00.004-07:00

(Above, Kirtland’s warbler male at a new Adams County site, June 12 2009.
Photo by USFWS; Joel Trick)

*

Want to know how many Kirtland's Warbler individuals were seen in WI this past 2009 breeding season?

Which counties?

How the Kirtland's third consecutive year of documented nesting in the state suggests this federally endangered songbird is now an annual nester in Wisconsin? -- in addition to, of course, nesting yearly in at least 12 Michigan counties (where at least 1,803 individuals were confirmed in 2009).

If so, please feel free to visit the following WI DNR link:

http://www.fws.gov/midwest/GreenBay/kiwa/2009Summary.html

Warbler Guy, do you know when the warblers begin their autumn migration?

2009-08-25T22:42:00.005-07:00

Good question, Neal in the “Midwest,” per your question in the “comments” section of the 8/7/09 article I authored here.

Wood-warbler migration actually begins in the summer by July or August for many species, if you also add in their initial travel in various directions away from breeding grounds (i.e., a behavior that is called “dispersal”). That is to say, unlike the more direct, dawdle-free behavior wood-warblers exhibit as they travel north on favorable tail-winds during spring migration, their post-breeding migration south is often a stuttering, stop-and-start, protracted itinerary.

Weather patterns in August through early October are a principal factor as to when many bird species (including wood-warblers) initiate migration and, subsequently, how far they travel on each segment of their southward night-time journeys. With north and northwest winds at their backs, wood-warblers may travel as many as 100 to 150 miles during a night’s journey.

Then again, feeding layovers for one or more days may occur where wood-warblers find abundant food resources. Likewise, binge eating sessions may be required when their body fat reserves deplete. Excess rain and unfavorable wind conditions also force wood-warblers into holding patterns until conditions improve.

Given the background information mentioned above, note it’s merely a brief and general summary of autumn bird migration patterns. More exact, consider that post-breeding season migration is an obligatory behavior most wood-warblers perform following dispersal from their breeding grounds.

Greeting the season’s initial freezing low temperatures, wood-warblers rudely discover their primary food source — insects, during the breeding season — rapidly disappear from the landscape. Consequently, migration emerges as an imperative survival behavior.

How many warblers migrate? For the majority of North America’s (north of Mexico) 52 annually present warbler species, their journeys begin by mid- to late summer (at the earliest) and no later than early to late autumn. So, for example, “early birds” such Yellow Warbler may begin dispersing/migrating in July, while other populations of the same species may wait until early October to leave for southern latitudes where they’ll spend the non-breeding season.

Other late summer, early-to-leave migrants include Tennessee Warbler, American Redstart, and Louisiana Waterthrush, all of which begin dispersing from northern breeding territories in July. True, uninterrupted migration toward “winter” habitat may not occur for these species (and many other North American wood-warblers) until beyond July and as late as October (and, more rarely, November and December) for some populations.

Only a handful of warbler species either do not migrate or remain annually (or periodically) throughout the winter in higher latitudes as far north as southern Wisconsin, Ohio, New York, and some New England states. This select club of bravehearts includes at least one subspecies of the Common Yellowthroat (among its 13 subspecies that live in North America), Yellow-Rumped Warbler, Palm Warbler, Orange-Crowned Warbler, and Yellow-Breasted Chat.

Which wood-warbler is the earliest to leave its breeding grounds? A leading contender is a subspecies of Orange-Crowned Warbler populations that breeds on the West Coast. Where it breeds in the San Francisco Bay Area, for example, Orange-Crowned often leave its dry and dormant environs by June, retreating to foothill and Sierra Madre mountainous habitat as intermediary “staging ground” habitats where cooler and moister conditions dominate and, thus, host abundant insect food resources.

For more details about the typical annual dates when each North American breeding wood-warbler disperses and/or migrates, see Jon Dunn and Kimball Garrett’s “Warbler” field guide (A list of the best warbler field guides and resources appears in a 10/21/08 article on this blog, so please feel free to scroll down the page and click multiple times on "older posts" to find it.).

More simplified information relating to autumn migration times for most USA-breeding wood-warbler species appears in a “Warbler Tips ID Chart” at my Web site: www.warblerwatch.com (After arriving at this site’s home page, click on the button title “Warbler Tips ID Chart.”)

Can you please share the answers to your latest quizzes?

2009-08-07T13:54:00.002-07:00

Yes, Jeremy S. (Tucson, AZ). Here’s the answers:

1. Can you name the two hybrid forms that sometimes result when Golden-Winged and Blue-Winged Warbler mate?

Answer:

Lawrence’s and Brewster’s

2. Can you name two wood-warbler species that are breeding endemics to one USA state?

Tropical Parula and Golden-Cheeked

3. On the West Coast, which wood-warbler is one of the earliest dispersing species after nesting?

Answer:

Orange-Crowned Warbler, given many disperse and/or migrate from the Bay Area by June.

4. Among the species listed in the 5/29/09 article, which one is considered extinct?

Answer:

Bachman’s Warbler

5. Common Yellowthroat was often previously named differently in many field guides as XXXXXX Yellowthroat?

Answer:

Maryland Yellowthroat

6. Beyond Michigan's breeding population, where else do researchers believe the Kirtland's Warbler regularly to periodically breeds?

Answer:

Wisconsin (as only one documented nest has been found in Ontario during the 1945 breeding season), while Kirtland’s has bred from 2007 through 2009 in Wisconsin.

7. Which common wood-warbler's breeding range is split into an eastern and western subspecies breeding population?

Answer:

Nashville Warbler, as its two USA subspecies are split into separated (allopatric) populations while nine Yellow Warbler species occur in the USA among the 43 total subspecies within North, Central and South America.

Warbler Guy, do you know why New World warblers are usually more colorful than Old World warblers?

2009-08-07T11:50:00.004-07:00

(Townsend's Warbler, above)

Good question, Antoine (in Richmond, VA).

The answer is not obvious nor proven in scientific research.

My explanation relates to how birds evolved and new species became established throughout North America (i.e., a portion of the New World) over eons of time.

As a first step, think about the geographic spot or “epicenter” where our North America wood-warblers originated. That area is the Appalachian Mountain region that served as breeding areas to which tropical species of wood-warblers (such as the colorful Yellow and Black-Throated Green Warbler, to name just two of many species) began migrating and breeding within the distant past.

In turn, new, evolving wood-warbler species spread throughout North America as they colonized habitat when the glaciers melted within northern latitudes 12,000-18,000 years ago. Generation after generation of breeding isolation of these new, pioneering populations from one another allowed distinct appearances to flourish as new species.

So, for instance, “sister,” look-alike, colorful species such as the Black-Throated Green, Hermit, Townsend’s, Golden-Cheeked, and Black-Throated Gray Warbler are considered close first-cousin relatives – though all primarily breed in distinct geographical areas throughout North America that do not overlap.

In fact, experts consider these five warblers a “super species,” with the Black-Throated Green the initial precursor from which the other four look-alike species evolved and spread west and north throughout North America from their Appalachian origins.

As for the generally drab, uncolorful appearance of Old World warbler species (Sylviidae family) that primarily breed in Eurasia, their evolution occurred in a similar fashion to the aforementioned progression of our New World North American wood-warblers (the majority of which occur in the Parulidae family). That is to say, one or more drab, uncolorful original warbler species in the far past were the root species of the evolutionary tree from which other multiple species evolved and spread throughout Europe and Asia.

In short, it’s mere geographical luck that the USA’s location is within the latitudinal migration pathway that colorful neotropical/equatorial New World species chose as they evolved their migrational routes from the south in search of northern breeding territories.

Best Buys: Warbler Books

2009-08-05T10:53:00.003-07:00

Which are two of the best wood-warbler books?

Here's two covers of publications I own and use often:

- Warblers, Jon Dunn & Kimball Garrett

- Warblers of the Americas: An Identification Guide, by David Quinn, David Beadle, Jon Curson

Difficult Decisions: Identifying Female Warbler Species

2009-07-28T12:56:00.002-07:00

Which are the most difficult wood-warbler female species to identify from one another?

All rise and bow to the Lord of Warbler Identification, as how doth one begin to compile such a lengthy list?

It includes such opponents as Wilson’s vs. Hooded; Yellow-Rumped vs. Cape May; Common Yellowthroat vs. Wilson’s; Wilson’s vs. Yellow; Bay-Breasted vs. Blackpoll (in late summer/autumn) – and I’ve just begun to scratch the surface of this identification game conundrum.

An interesting treatise on this topic appears at the following web site address:

http://www.tucsonaudubon.org/birding/duos25.htm

Here, the author (Larry Liese) explores how to distinguish female Yellow, Wilson’s, and Common-Yellowthroat from each other.

(The illustrator of the above graphic is George C. West.)

Which wood-warbler populations have fallen precipitously in recent years?

2009-07-21T23:05:00.005-07:00

If your answer included "Cerulean Warbler," then you're correct.

Based on information at Cornell of Ornithology's web site (http://www.birds.cornell.edu/cewap/index.html), this Neotropical migratory bird species continues to experience population declines in parts of its range. However, given the Ceruleans low population density and patchy distributions, accurate population trends are difficult to estimate. One ongoing, annual monitoring program -- the Breeding Bird Survey, coordinated by the US Geological Survey -- has compiled data that suggest a 3.8 percent annual decline in populations of Ceruleans since 1966. To adequately protect this species more information is needed about its habitat requirements, breeding biology, and population status, the Cornell web site suggests.

To determine the number of breeding pairs and productivity, describe nesting habitat, and identify potential threats to the population and its habitat, the Cerulean Warbler Atlas Project (CEWAP) employed enthusiastic birders and biologists to survey known and potential Cerulean Warbler breeding sites from 1997 to 2000.

Results from CEWAP will be used to produce management guidelines for Cerulean Warblers. As of December 2000 you can download the final report, "An Atlas of Cerulean Warbler Populations," by conducting a Google search with the aforementioned title in quote marks.

Lucky 19: Kirtland's Warbler Update in Wisconsin

2009-07-11T09:41:00.007-07:00

(Above, a fledgiing Kirtland's Warbler in Adams County, Wisconsin. Copyright Joel Trick, Wisconsin DNR.)

*

According to a Wisconsin DNR news release from July 6, 2009, 19 Kirtland's Warbler young have hatched in the state this breeding season.

(As background information for the uninitiated, historically and through 2006, Michigan was considered the endemic breeding range of this species. Only periodic, non-annual sightings were reported in Ontario (including one nesting record in 1945) and Wisconsin, with no documented nests ever found in Wisconsin. This scenario changed in 2007 when Kirtland's was confirmed as a nester for the first time in Wisconsin.)

Here's more information about the ongoing monitoring in 2009 of Kirtland's Warbler within two Wisconsin counties:

Adams County

Wisconsin Kirtland’s warblers have had an extremely successful nesting season in 2009, and have already surpassed the reproductive output of last year. As of today, at least five Adams County nests have fledged young, including two nests that each produced four young over the weekend. So far a biologist has determined that the nests that have fledged contained a total of 19 young when checked just prior to the young leaving the nest. Another nest that is currently being incubated is expected to hatch within the next week or so. This nest is the renesting effort of a pair that had previously been parasitized by cowbirds. One nest that was expected to fledge soon was empty today, and the behavior of the adults suggests it may have been lost to predation. The biologist has currently been unable to find the nest of one additional pair at the site, but he will continue to search in the days ahead.

Marinette County

Male Kirtland’s warblers are known to be present at two separate sites in Marinette County, and each has previously been observed with a female. On Thursday, a DNR volunteer monitor found a nest containing three eggs at one of these sites. Finding eggs at this late date suggests that this may be a renest after an early failure. If successful, this would be an important nesting record for Marinette County. We will continue to monitor this nest to determine its outcome.

Which wood-warblers are known to feed on fruits and nectar?

2009-07-08T15:05:00.006-07:00

Many of North America’s wood-warblers consume fruit and nectar, especially during the non-breeding season.

Three of the most notorious species are Dendroica congeners Yellow-Rumped, Black-Throated Blue, and Cape May Warbler. (Some Vermivora genus members, too, are known for eating fruits/nectar, given they probe well with longer, thinner bills than Dendroica genus members’ that have bills primarily adapted for insect eating.)

Yellow-Rumped populations during the non-breeding season often remain in far northern latitudes in comparison to other wood-warbler species that are obligatory migrators forced to vacate areas where they breed. Yellow-Rumped is often able to remain in northern climes throughout the winter (e.g., Wisconsin and New England during some, but NOT all, non-breeding seasons) because, depending on its location, may subsist on foods such as poison ivy berries, wax myrtle berries, and/or privet berries – fruits, in fact, from which the majority of other songbirds are unable to derive much energy.

Black-Throated Blue, likewise, are documented to
eat small berries and fruits. They also feed at flowers, possibly for nectar or insects. During the non-breeding season in the Dominican Republic, this species feeds frequently on honeydew-like excretions from scale insects.

As for Cape May, non-breeders are often easily observed and are known to feed on nectar, among other things, taken up by means of a semi-tubular tongue. They also eat insects and fruit from Cecropia trees, grapes and grape juice, and tree sap. In some cases, this species has caused damage to commercial vineyards in Indiana, Pennsylvania, and W. Virginia by puncturing grapes, thereby damaging all grapes not bagged.

As a personal observation note, I remember several autumns in Wisconsin and Maryland when I watched transient Black-Throated Blue feeding on various berries. Staking out the same patch of shrubs each autumn invariably resulted in the presence of watching the berries disappear over a few days – while I enjoyed seeing female, male, and hatch year individuals of this species up close.

Can you name a common wood-warbler that migrates early throughout the USA?

2009-06-30T10:27:00.001-07:00

If you said “Yellow Warbler,” then you’re correct.

Rather than merely identifying this species as among the earliest “fall migrants” within the wood-warbler family, it’s apt to state the Yellow Warbler is an early “summer migrant.”

Dispersal and/or migration begins by mid- to late July throughout the majority of its eastern USA breeding range.

Migration of Yellow Warbler on the West Coast is not as early, typically initiating in August and peaking later in the month and into early September.

In addition, note this species has protracted migration, as some tardy individuals have been noted in Pennsylvania as late as October 1st and into late October from sightings in South Carolina and Florida.

Earliest arriving transients from the north into Mexico have been detected by late July. Most individuals, however, arrive in non-breeding territory by August, with peak numbers returning in September and October.

Wisconsin Kirtland's Warbler Nesting Update

2009-06-24T10:51:00.005-07:00

. . . largest total of nesting Kirtland's males is confirmed in latest report

*

According to a Wisconsin Dept. of Natural Resources news release, bird monitors have confirmed the presence of six Kirtland's Warbler nests, with four hosting nestlings and two hosting eggs.

Eleven males in the state have been banded.

To read the news release, go to:

http://www.fws.gov/midwest/greenbay/kiwa/update22June2009.html

Of course, historically and through 2006, Michigan was considered the endemic breeding range of this species.
Only periodic, non-annual sightings were reported in Ontario and Wisconsin, with no documented nests found.
This scenario changed in 2007 when Kirtland's was confirmed as a nester in Wisconsin.

The presence of the aforementioned breeding individuals marks the third consecutive season of documented Kirtland's in Wisconsin.

Spring Confirmation: Wisconsin's Kirtland's Warbler Population Increases

2009-06-09T13:54:00.004-07:00

. . . as many as 18 individuals seen this breeding season

*

The Milwaukee Journal's Outdoor Writer Paul Smith features an update on this season's Kirtland's Warbler nesting confirmation.

It is the third consecutive breeding season that the normally Michigan endemic wood-warbler has been confirmed breeding in the state -- which historically was graced with only periodic sightings of this endangered species.

To read Smith's article, go to:

http://www.jsonline.com/sports/outdoors/47268492.html

Which wood-warbler species are members of the “Watch List?"

2009-05-29T11:56:00.002-07:00

(As a Watch List member, Hermit Warbler (above photo) populations are stressed by ongoing habitat loss in both their breeding and non-breeding range.)

Thanks for the question, Kerry W. from Polesville, PN.

Answer:

Coordinated by the Audubon Society and the America Bird Conservancy, the Watch List aims to rally conservationists around America's most imperiled birds. In so doing, the Watch List employs the latest available research from the bird conservation community along with citizen science data from the Christmas Bird Count and the annual Breeding Bird Survey to identify species in the continental U.S. and Hawaii that are in need of immediate conservation help. It is a call to action to save species fighting for survival amid a convergence of environmental challenges, including habitat loss, invasive species and global warming.

The current wood-warbler family members on the Watch List:

Bachman's Warbler
Blue-winged Warbler
Golden-winged Warbler
Virginia's Warbler
Colima Warbler
Lucy's Warbler
Golden-cheeked Warbler
Hermit Warbler
Grace's Warbler
Kirtland's Warbler
Prairie Warbler
Bay-breasted Warbler
Cerulean Warbler
Prothonotary Warbler
Worm-eating Warbler
Swainson's Warbler
Kentucky Warbler
Canada Warbler
Red-faced Warbler

What “strange” common names were previously designated for some of our wood-warblers?

2009-05-13T16:38:00.004-07:00

(The above Black-Throated Blue female's vastly different appearance in comparison to a definitive male of the species is suggested to be the reason John James Audubon named it a different common name, the Pine Swamp Warbler.)

Common Yellowthroat was once often referred to as Maryland Yellowthroat. John James Audubon mistakenly named two Yellow Warblers as Children’s Warbler. In another instance, Audubon misnamed two juvenile Yellow Warblers as Rathbone’s Warbler.

Audubon was not alone in his naming confusion. Beyond Audubon, naturalist/painter Alexander Wilson also made his share of identification mistakes. Both of these luminaries – as well as other contemporary birding experts in bygone eras – are to be excused because during their tenures little was known about the relationship between plumage changes and corresponding definitive field characteristics.

Audubon’s failed nomenclature decisions periodically continued to surface as he gathered specimens for his paintings. Originally calling a bird specimen he collected in Pennsylvania the Pine Swamp Warbler, he later realized his subject was truly a Black-Throated Blue Warbler.

Later, Audubon was misled by Wilson’s naming procedure into thinking a Blackburnian Warbler was worthy of being designated a new species, the Hemlock Warbler. Audubon, in fact, was never able to correct this misnaming mistake. Another misplay hearkens to May 1812, when Audubon caught a wood-warbler specimen that he named Vigor’s Warbler in honor of Nicholas Vigor, an English naturalist. More correctly, Audubon’s find was an immature Pine Warbler. His confusion was probably the result of the collected individual being in vastly different habitat than its usual pine/needle tree haunts.

Even the Canada Warbler was originally misnamed by Audubon. When he first drew the bird as it perched on the fruiting branch of a magnolia, Audubon suggested it be named the Cypress Swamp Flycatcher. Later he changed his mind, renaming the bird as Bonaparte’s Flycatcher only to again change its designation to Bonaparte’s Flycatching Warbler.

Eventually, it was confirmed that Audubon’s specimen was instead a young female Canada Warbler. Eight years later, Audubon painted the same species and mistakenly called it a Canada Flycatcher.

What are the answers to the most recent quizzes appearing on the right side of this home page as you scroll from top to bottom?

2009-04-27T22:43:00.001-07:00

Beyond Michigan's breeding population, where else do researchers believe the Kirtland's Warbler regularly to periodically breeds?

Answer: WI & Ontario

*

Which common wood-warbler's breeding range is split into an eastern and western subspecies breeding population?

Answer: Nashville

*

Which sequence of weather conditions typically result in a "fallout" of wood-warblers during the spring on the Gulf Coast?

Answer: Warm, southerly breezes followed by a cold front/northerly winds.

*

If it's not a wood-warbler, then into which taxonomic placement has Yellow-breasted Chat previously been proposed?

Answer: Tanager family

*
Which "New World" wood-warbler species has the most extensive breeding area?

Answer: Yellow

*

Unlike Blackpoll that undertake a long migration (see 1/8/09 article), which wood-warbler has populations that do NOT migrate?

Answer: Common Yellowthroat

Where in Michigan might I see Kirtland’s Warbler and what are the best dates to go?

2009-04-21T12:51:00.003-07:00

Thanks for the question, Laurie in Detroit, MI

Answer:

Given the good news (from a Michigan DNR news release from September, 2008) that Kirtland’s Warbler populations are at an all-time high of 1,791 singing males, your chances of detecting them are excellent. Most of the population nests in 12 lower Michigan counties within central-northcentral Michigan (Alcona, Clare, Crawford, Grand Traverse, Iosco, Kalkaska, Montmorency, Ogemaw, Oscoda, Otsego, Presque Isle, and Roscommon) and five upper Michigan counties (Chippewa, Delta, Luce, Marquette, and Schoolcraft). (However, nine individuals were detected in WI in 2008 and one in Ontario.).

The initial two weeks of June are the ideal time to visit the Kirtland’s breeding grounds, but a later visit through the first week of July could also yield viewing results.

Note that guided tours to view the Kirtland’s Warbler leave from various locations. To find out the schedule, contact the DNR Wildlife Division, Natural Heritage Program, Box 30180, Lansing, MI 48909, or visit the DNR Web site: www.michigan.gov/dnr.

Why is the diversity of wood-warblers greater in eastern than western USA forests?

2009-04-08T17:23:00.003-07:00

Excellent question, Don Y. of Houston, TX.

Answer:

Although different perspectives for this phenomenon have been initiated by researchers, a summary of the leading ones follow:

1. The epicenter of wood-warbler colonization occurred initially in eastern USA forests, so over time more wood-warbler species have evolved in this area in comparison to western habitats.

The above statement is an oversimplification of a theory that is based on two million years of bird movement/migration in North America since the Pleistocene glaciation episodes occurred. In this regard, theorists believe the eastern wood-warbler species were present before the most recent four glacial advances. As the ice sheets advanced, separation of some species may have occurred or movement was enhanced, so that the splitting off of sibling wood-warbler species occurred. However, this process is slow and, thus, colonization of western USA areas has occurred with less diversity of species than those remaining (and continuing to evolve) in eastern habitats areas.

2. Moisture is generally far more abundant during the breeding season in eastern forests than western ones. As a result, more insect prey resources occur in eastern than western foliage where many species of wood-warblers forage.

3. Related to the above, #2, the foraging method called “foliage-gleaning” is specific to the largest quantity of wood-warblers occurring in North America, namely the Dendroica genus of wood-warblers. More than half of this area’s 52 annually occurring wood-warblers in North America (north of Mexico) are members of this genus. Given the far greater opportunity for “foliage gleaning” to occur in eastern forests than western ones (due to the composition of forests and the tree species they host), more wood-warbler species were able to establish themselves and evolve in eastern USA habitats.

How did the Hermit Warbler get its name?

2009-03-31T15:20:00.003-07:00

Thanks for the question, Jim D. in Delvan, WI.

Answer:

Perhaps the reason relates to how it’s often easier to hear than see them, as Hermit Warblers typically forage individually high in the tree tops — hence, the common name that John Kirk Townsend first described when collecting this species in 1837 near Fort Vancouver (now Vancouver, WA).

Considered part of the Black-Throated Green “super species” — along with Black-throated Green (Dendroica virens), Golden-cheeked (D. chrysoparia), Black-Throated Grey (D. nigrescens) and Townsend’s (D. townsendi) warbler — the Hermit Warbler breeds in coniferous forests of the Coast, Cascade, and Sierra Nevada mountain ranges of southern Washington, Oregon, and central and northern California.

Where it occurs with Townsend’s Warbler within the s. Washington Cascade Mtns., Olympic Mtns., and central Oregon Cascade Mtns., Hermit Warbler may be losing populations as it is replaced and outcompeted by its first cousin. Studies by S. Rowher and C. Wood from 1994 to 1996 in this region indicate that 80 percent of adult Townsend’s and only 53 percent of adult Hermit paired and maintained their territories long enough to reproduce successfully. Other data relating to aggression behavior and hybrid zone analyses further supports Rohwer and Wood’s conclusions. Another reason for the reduced local populations of Hermit’s may be the result of reduced suitable breeding habitat in portions of its home range.

Nonetheless, in other portions of its range where Townsend’s Warbler does not breed, Hermit Warbler population densities appear to be stable, according to Breeding Bird Surveys (BBS) conducted in the last 30 years. However, it’s important note that BBS surveys are limited to routes where roads occur, so more comprehensive surveys of the Hermit’s total abundance do not exist. In addition, given the Hermit Warbler’s inherent small population worldwide and narrow geographic distribution, it is not considered abundant or common in most portions of its home breeding range.

Latest Warbler Quiz Answers

2009-03-16T12:27:00.000-07:00

Below, you’ll see correct answers to recent quizzes that appear on the right side of this page (in order, from the most recent quiz to older ones):

Which "New World" wood-warbler species has the most extensive breeding area?

Answer: Yellow Warbler

Unlike Blackpoll that undertake a long migration (see 1/8/09 article), which wood-warbler has populations that do NOT migrate?

Answer: Common Yellowthroat

What behavior displayed by American Redstart is different than most other songbirds?

Answer: Some females sing

Which wood-warbler species spends the winter in large numbers in higher latitudes than any other wood-warbler?der members?

Answer: Yellow-rumped Warbler

Returning Wood-Warblers In The Bay Area

2009-03-06T14:34:00.006-08:00

Birders are reporting the initial appearance of northbound migrating wood-warblers to the Bay Area this week.

Newly-arrived ORANGE-CROWNED WARBLERS are currently joining brave over-wintering populations, with Oak-Bay woodlands one of the best habitats to hear and seem them.

Note the annual date range of first-returning migrants for this species in Marin County (the initial county north of the Golden Gate Bridge) is 2/18 (earliest detection) through 3/16 (latest detection), according to Dave Shuford’s “The Marin County Breeding Bird Atlas.”

Soon, other nesting wood-warblers of the Bay Area shall also appear, with their identities and date range of arrivals in parentheses below:

- WILSON’S (3/10 – 4/8) (shown above)

- BLACK-THROATED GRAY (3/31- 4/27)

- YELLOW (4/8 – 4/23)

- MACGILLIVRAY’S (4/3 – 4/30)

For a comprehensive list of arrival dates for Marin County landbirds, feel free to visit my Web site (www.warblerwatch.com) where there’s a button that provides access to the Atlas’ chart (page 39).

Who’s ready for a brief wood-warbler quiz?

2009-02-11T16:26:00.003-08:00

It’s the Q and A portion of the day, so feel free to satisfy your wonderment with the following questions (answers appear far below):

1. To which family do some taxonomists believe is most closely related to wood-warblers?

2. If you include North, Central, and South America, and the West Indies, how many wood-warblers exist?

3. Although most wood-warblers possess small bills, which two species have more robust ones?

4. Which common wood-warbler has rictal bristles (like flycatchers) to help it sense prey while pursuing insects?

5. Although most songbirds have ten functional primary flight feathers on each wing, how many do wood-warblers possess?

6. Among the 53 typical annual breeding North American wood-warblers, what’s typical about their breeding behavior in contrast to Central and South American wood-warbler species?

ANSWERS:

1. Some taxonomists place wood-warblers closest in relation to the tanager family, Thraupidae (sometimes treated as a subfamily, Thraupinae, of Emberizidae). Other researchers believe they are nearest to the New World finches family, Emberizidae.

2. 126 species amidst 28 genera.

3. Yellow-breasted Chat and Yellow-Rumped Warbler.

4. American Redstart.

5. Nine.

6. North American wood warblers remain monogamous for the breeding season, while Central and South American pairs may persist together for longer periods.

Wilson’s Warbler: Abundant, Yet Vulnerable

2009-02-03T14:13:00.002-08:00

You might think the Wilson’s Warbler is one of the most abundant warbler species while traveling through Alaska, most of Canada, and south through the western USA to southern California and New Mexico. Your supposition would largely be correct.

But long-term trend analysis indicate recent population declines, especially in the western portion of the species’ range. The most likely problem is large-scale destruction of riparian habitat.

Nesting on or near the ground at elevations that vary from sea level to the alpine zone, the three subspecies of Wilson’s Warbler encompass a wide geographical area that spans from eastern Canada to Alaska and portions south into Utah, New Mexico and central California.

Interestingly, the subspecies may occur together in non-breeding range, with all three subspecies possible in Panama.

Although it shares its genus name – Wilsonia -- with other wood-warbler species – (Canada and Hooded), Wilson’s is by far the most common. All three species possess rectal bristles (small , highly-sensitive feathers at the base of the bill) that are utilized during “flycatching,” a foraging behavior that can sometimes help with field identification.

Mr. Warbler, what’s the difference between “New World” and “Old World” warblers?

2009-01-28T12:16:00.004-08:00

Thanks for the question, Barbara S. in Spokane.

Noting the New World is a geographic designation corresponding to the Western Hemisphere, Old World warbler species live within the Eastern Hemisphere areas of Europe, Asia, and Australia – with only a few species (e.g., gnatcatchers) existing in the New World/Americas.

Approximately 350 Old World warblers occur in the Sylviide family. New World warbler species total around 120 species and most of them are in the Parulidae family.
(Approximately 52 are annually seen in the USA north of Mexico, with the most common being Yellow, Common Yellow-throat (above photo), Yellow-Rumped, among others.)

In fact, the Olive Warbler (the sole Peucudramidae family member) is the only non-Parulidae family species among North American wood-warblers to occur north of Mexico.

Note there’s also the Australasian warblers in the Acanthizidae family that include gerygones, thornbills, and scrubwrens,.

This family is native to Australia, Indonesia, New Zealand, and the south-west Pacific. Australia hosts 35 endemic Acanthizidae family members and New Guinea 15. A single species is found in Vanuatu, New Caledonia and the Solomon Islands, and three species occur in the New Zealand region, including endemic species in the Chatham Islands and Norfolk Island. In Asia two species are restricted to Indonesia and another is found in the Philippines and on mainland Asia. Most species are not migratory, with the exception of the gerygones.

Which wood-warbler travels the longest migration route?

2009-01-08T17:33:00.002-08:00

Thanks for the question, David in Studwell, MN.

The answer: Blackpoll

Autumn studies of the routes south-traveling Blackpoll take have been extensive. Through banding at stations where the same individual has been studied, researchers have determined some Blackpolls travel more than 5,000 miles one way from Alaska to Brazil.

For many Blackpoll migrating populations, migration occurs over the Atlantic Ocean from the northeastern United States to Puerto Rico, the Lesser Antilles, or northern South America.

This route averages 1,500-2,000 miles over water, necessitating a potentially non-stop flight of up to 88 hours. To complete this migration feat, many Blackpolls nearly double their body mass and prefer to take advantage of a shift in prevailing wind direction to direct them to their destination.

What’s an example of a “superspecies” in the wood-warbler family?

2008-12-24T11:33:00.004-08:00

(The Black-Throated Gray Warbler in the above photo is one of five species within the Black-Throated Green superspecies group.)

Thanks for the query, Ms. Jones (in Santa Barbara, CA).

Think of a superspecies as a group of related species that evolved from a common ancestor, but live in distinct ranges apart from each other. A good example of a superspecies is the Black-Throated Green Warbler group that includes this species as well as Townsend’s, Hermit, Golden-Cheeked, and Black-Throated Gray Warblers.

Each of the latter four species in the above group is thought to have evolved from its Black-Throated Green ancestor. As this species expanded from its southeastern USA deciduous forest territory into coniferous forest created by the most recent glacial advances, isolation occurred among populations. As generations of separated populations slowly spread west and north throughout lower North America, each population became a divergent “island.” Gene flow ceased as reproductive isolation caused speciation to occur over eons. The resulting five species share various field marks, but also express their own unique characteristics.

Nonetheless, despite their status as species, hybridization sometimes occurs among species within a superspecies, including the Black-Throated Green superspecies wherein populations of Townsend’s and Hermit hybridize in Oregon and Washington. To simplify, where both species occur, over time Townsend’s appear to usually dominate and increase in number.

More technical, the five species within the Black-Throated Green superspecies have parapatric distributions. That is to say, each of the five species has ranges that do not significantly overlap but are immediately adjacent to each other (and/or occur together in a narrow contact zone, with the aforementioned reference to Townsend’s and Hermit Warbler hybridization a scenario where overlapping occurs).

To learn more about this subject, read a classic article by R.M. Mengel titled “The probable history of species formation in some northern wood warblers.” One source where this article appears is in a 1964 edition of “Living Bird” (page 943).

Is the American Redstart a vagrant in the western USA?

2008-12-17T12:39:00.003-08:00

Answer:

Thanks for the question Lori Anne (in Seattle).

Although many eminent, well-respected authors suggest, for example, a California sighting of American Redstart deserves a “vagrant” status designation*, I beg to differ.

(* = vagrant status applies to a bird species that is found far from its typical breeding or non-breeding area.)

That’s because my research suggests small populations of this species periodically to annually nest in small numbers in n.w. CA. In addition, other breeding range individuals occur as far west as s.w. Idaho, Oregon, and Washington.

As a result, I believe it’s more appropriate to refer to autumn and winter sightings of this species in northern California as “casual visitors.” That term qualifies a bird species’ status as one that is slightly removed geographically from where it is expected to be seen in either breeding or non-breeding range.

Ultimately, it’s possible a Bay Area (e.g., Point Reyes National Seashore) sighting of this species could be an individual that spent the breeding season in farther north latitudes, such as the aforementioned n.w. CA area (or Alaska, more probably, where populations in greater abundance breed).

In any event, the entire species of American Redstart are thought to be locally abundant in much of their breeding range, especially if suitable habitat remains. However, it should be noted that populations have declined where forests have been fragmented by development and where urbanization has replaced habitat.

Is it possible to distinguish the call notes of Audubon’s vs. Myrtle Yellow-rumped Warbler during the non-breeding season where they occur together?

2008-11-24T06:59:00.001-08:00

Answer:

Obviously, these birds are NOT singing during the non-breeding season, but you do often hear loud chip or call notes where Audubon’s and Myrtle Yellow-Rumped Warbler patrol during the non-breeding season.

In many cases you can hear how the Myrtle (one of the subspecies of the Yellow-rumped Warbler species) has a flatter and softer chip note than the Auduon’s.

The “ch” component of the call note is weaker for the Myrtle and it often gives many calls in rapid succession.

However, be careful. Intergrades (individuals that display visual characteristics specific to both Audubon’s and Myrtle) may announce call notes of the other subspecies. In other words, it’s possible to see a bird that looks like an Audubon’s, but it’s call note sounds like a Myrtle. This individual could likely be an intergrade.