Sunday, December 22, 2019

Warbler Guy, do female warblers sing? If so, how many singing warbler females occur? Or only males sing? What about other singing female songbirds? Yes? No?

Yes, Hanna (in Fargo) it's true — some female wood-warblers sing.

But not many. 

Only two of our New World wood-warbler family members sing — Yellow and American Red-start — according to Jon Dunn and Kimball Garrett, author of the "Warblers" field guide (Peterson Guide Field Guide Series, Houghton Mifflin, 1997).

Then again, note Dunn and Garrett's findings are 22 years old. In recent years, researchers have witnessed several more female songbird order members expressing song. So, it's possible one or more other wood-warbler female species also perform song renditions.

Why do fewer females than males sing among songbirds? Speculation abounds, but one recent theory is that the majority of females previously sang, but through time lost their ability to do so
while males retained song as a primary function.

Next, note that wood-warblers are like most other songbirds. They experience a period of practicing a song in a stage that is called "plasticity."

Depending on the species of wood-warbler, true, definitive adult song is achieved by no later than the commencement of the following breeding season after a newborn singer arrives in a previous year's brood.

When that moment of virtuosity appears, it's called "crystalization" (when complete, full, learned song can be repeated by an individual).

Now there's a magnificent term that rings a chord of delight in any birder's heart.

(I still haven't revealed who the female singing species of wood-warblers are on the landscape. If you wish to know before the quiz deadline occurs, please feel free to email me:

Regards, Daniel Edelstein

Birding Guide


Avian Biologist

Tuesday, November 26, 2019

Warbler Guy, where can I read about nesting warblers? Get warbler information? Learn about warbler migration for each warbler species; Identify mystery warblers by reading about them?

Syd, you cannot go wrong by visiting:

This site features a comprehensive list of more than 720 North American species, with all of this area's Parulidae (warbler family) members present.

Yes, it costs money: $42 per year or $100 for three years.

Thumbs up. Way up. 

2. The Warbler Guide (2012, Tom Stephenson & Scott Whittle, Princeton University Press)

Comprehensive. A-1. Look on Amazon or many blog site that review this excellent field guide.

Email me with any warbler questions, of course, as I read this guide regularly....and I'm glad to answer your warbler questions:  danieledelstein@ (Feel free to see my "Warbler Tips ID Charts" at my Birding Links area at my home page.)

Wednesday, October 23, 2019

Warbler Guy, where do I learn about "reading" warbler songs (sonograms or spectrograms)? Is Warbler song easy to "read?"

Kathy, there's a one-stop shopping venue for all your edification needs:

Here, Nathan Pieplow, an erudite sound recordist and expert birder, highlights many "ear birding"
elements, including ways for you to easily read sonograms/spectrograms.

Please see his web site: and his recent book's are excellent on this subject: a) Petersen Field Guide to Bird Sounds of Western N. America and b) Petersen Field Guide to Bird Sounds of Eastern N. America.

The above web site is so good that it gets a top rating from Warbler Guy's advisory panel: me, myself, and I.

Seriously, reading and interpreting sonograms/spectrograms takes practice, but after a while you can
see the elements upon the page that originally looked like gibberish make sense.

Ergo, you'll quickly have no problems identifying a song sparrow classic song via its sonogram in comparison to a common yellowthroat's, and so on.

Other resources for identifying birds by sound and "ear birding" abound.....Some of my favorite are books by Dr. Donald Kroodsma, who authored the classic:
The Singing Life Of Birds.

Is warbler song easy to read on sonograms? Some people find them easier to comprehend than others. I think the above resources will help. My opinion is that some sonogram songs are easy to understand and others are more incomprehensible.

Monday, October 7, 2019

Warbler Guy, where are the most different kinds of warblers found? How many types or species of warblers exist? Are all warblers migratory or do some stay “close to home”...?

New World wood-warblers (that are not closely related to the various Old World warblers in the Eastern Hemisphere (e.g., Europe, Asia) are often identified to number as 112-115 species, occurring among 24-26 genera. The centers (or “epicenters”) of their breeding areas occur in eastern North America, the West Indies, Mexico and Central America, and Andean South America.

The majority of northern-latitude breeding species migrate, but many island and tropical species are sedentary. Many of these latter species remain close to their birthing areas or perform short-distance, post-breeding altitudinal/elevation migrations.

As for myself, I often see 20-30 wood-warbler species during early May when I return to homecoming birding forays in the Midwest (and, concurrently, attend the annual Wisconsin Society For Ornithology conference). This year, I was lucky to visit Wisconsin again on another week-long June jaunt similar areas in Door County, but achieved merely a single digit wood-warbler total. Likewise, my birding efforts in southern Wisconsin on my recent visit provided challenging warbler conditions, with Milwaukee County nearly devoid of warbler detections, except for probable nesting species such as American Redstart, Mourning Warbler, Bay-breasted Warbler, and Yellow Warbler.

In contrast, my n. CA residency, yields more warbler species during the breeding season — a result that surprises many people because the West is thought to host far fewer warbler species. For example, in Marin County (Bay Area) where I live, I often detect at least eight warbler species annually and, in the Sierra Nevada Mountains (near Yuba Pass and/or amid the Gold Lakes country off of Highway 49 near Bassetts), I sometimes successfully sleuth out nine warbler species.

Saturday, September 21, 2019

Warbler Photo Quiz..Can You Name These Warblers, Below?

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

Check back by 9/29/19 for the answers....or email me at

(See "Birding Links" pulldown menu for birding information)

Regards, Daniel

Consulting Avian Biologist


Birding Guide

Tuesday, September 10, 2019

Trick Photo Quiz....Can You ID These Birds? Which One Is NOT a Warbler? To Which Does The Non-Warbler Belong?

 . . and good day to all. . . and who wishes to vote on the ID of the following four wood-warbler photos, BELOW?

(See FAR below for answers...Wish to Share and Tell this quiz with your birding friends....Thank you in advance, Daniel Edelstein, Birding Guide

(Photos courtesy of Martin Meyers.)

Answers from top to bottom: Prothonotary Warbler and Yellow-breasted Chat, with 
the latter now in the Icteriidae family. It's no longer in the wood-warbler family (Parulidae).

Thursday, August 22, 2019

Warbler Guy: Now that "fall" southbound migration has begun, where's a GREAT web site to check rare bird sightings in the area where I live? Where I plan to bird soon on my upcoming birding vacation?

Stacey, great question, and here's a new web site where you can read rare bird reports corresponding to any USA state (to which you might travel for birding and wish to know which "cool" bird species are potential "hot" draws for you and other birders to sleuth out:

Jeff Gordon, the American Birding Association's (ABA) Executive Director, noted the importance of this new web site in the following linked article that goes to the ABA's web site where the latest rare bird report is featured at:

In this article, Jeff mentions the new web site goes beyond serving as a posting site for rarities.

I hope this helps (?)


Daniel Edelstein 

Birding Guide,

Consulting Avian Biologist (who possesses five survey permits) (USFWS permit # TE101743-0)


Certified Wildlife Biologist Assc
(Surveys, Permitting, Regulatory Services)

12 Kingfisher Ct. 
Novato, CA 94949 

415-382-1827 (O) 415-246-5404 (iPhone) 
(hosts my resume)
(My 12-year-old warbler-centric blog, featuring articles, warbler news, & photo quizzes)

Saturday, August 3, 2019

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?

Excellent questions, Jason. Answers: 1. The book “Rare Birds of California” is an fine 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.

(Above: Connecticut Warbler, courtesy of Wikipedia)

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.

To find this location, contact the park's rangers or email me:

Tuesday, July 23, 2019

Warbler Guy, do wood-warblers start migrating in late summer? Fall warbler migration begins when? Warbler migration in autumn starts in August? What about warbler dispersal vs. warbler migration? What's the difference?

Joey (in Chicago):

Interesting questions that you pose.

First, migration is different than dispersal.

Dispersal is post-nesting behavior when birds remain in the area where they bred, but have not yet migrated. Foraging is the principal activity, say, in July or August for these birds. Molting may be included as a post-breeding phenomenon for some dispersing individuals.

Migrating is moving with purpose to non-breeding grounds away from where birds spent the breeding season. Hence, true northern hemisphere neotropical migrant bird species migrate after breeding to non-breeding grounds before again looping back north again the following spring.

Seeking even more details about this subject? Please read below at the * area.

(* = Dispersal begins earlier than migration. Fledgings leave the nest and begin their independent lives while foraging BEFORE eventually migrating. So newborns may linger in an area near where they were born. By mid- to late-August at upper Midwest latitudes, some begin to migrate south while other species -- such as American Redstart, Palm Warbler, Yellow-rumped Warbler, among others — may have a protracted migration. These three species are among the latest to leave northern latitudes, with some Yellow-rumped and Palm remaining through November and December -- and, in recent years, some of both species persisting through Christmas Bird Count surveys in the upper Midwest (and even remaining throughout the winter in some cases). Pine Warbler may also persist late while sometimes feeding at seed feeders after an insect fauna is depleted with freezing temperatures.)

Now, let's discuss breeding vs. non-breeding ranges of wood-warbler species.

A nice resource to read about breeding vs. non-breeding ground ranges of wood-warblers is in Warblers (the field guide from 1998 by Jon Dunn and Kimball Garrett). Its information is dated in spots, but most of the text remains valid. As a more updated complement, I also refer to the fantastic The Warbler Guide (Tom Stephenson and Scott Whittle, Princeton University Press, 2013). This guide's range maps for migration and breeding/non-breeding ranges more accurate in some cases than Warblers, with more comprehensive photos for each species. You won't be sorry for purchasing both books.

Now, here's an illuminating example that incorporates the above information.

It's a past report from Ryan Brady, an ornithologist/bird researcher/scientist for the Wisconsin DNR. His late summer list of is below. See his list of 20 wood-warbler species that he noticed on 8/29/17 near Bayfield/Washburn, WI (near Lake Superior): (Then see more of my commentary, below.)

From: Ryan Brady <>
Subject: [wisb] 20 warbler sp. - Bayfield County
Date: Wed, 30 Aug 2017 01:50:37 +0000

An excellent flight last night brought 20 species of warblers to the trails around my property this morning, including Golden-winged, Blackpolls, Bay-breasteds, Mournings, Palms, Pine, and more. Thrushes were on the move in the morning fog, yielding some Swainson's and my first Gray-cheekeds of the fall. Also had my first Lincoln's Sparrow and a nice push of 3 Yellow-bellied Flycatchers.

Full eBird checklist at

Ryan Brady
Washburn, Bayfield County, WI

I hope these answer your questions, Joey?

In closing:

It's time for the D & M Show, so to speak (Dispersal & Migration Show.....(!) ).

Enjoy the birding, everyone....

Regards, Daniel (hosts my "Birding Tours" that I have led as a Birding Guide since the 1980s

Wednesday, July 10, 2019

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

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

Giff's "Warblers" site is found at:

(male Magnolia Warbler, below)

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:

Sunday, June 16, 2019

Warbler Guy, what's Bird Genie and which bird apps are also a good idea to buy?

Joe (in Seattle)...Good question, as I often get asked by birders this same question.

As you may know already, the Cornell Lab of Ornithology recently published Bird Genie, an app that uses sound recognition to suggest the ID of birds after you record them.

It works well from reports I've read, but it's limited in the number of individuals that can correctly be identified.

For beginning birder, I imagine it's "cool," a wondrous invention.

But for evolved birders, I doubt much value can be secured.


Because their ears are typically trained for "ID By Ear" beyond the level of Bird Genie, in my humble opinion.

That's not to suggest future iterations of Bird Genie may not be worth buying.

It's simply the current version is not "Thumbs Up" yet for me to recommend.

Just my two cents....or, perhaps more apt: Just my SAVED two cents.
(I think Bird Genie is $9.99 (?) )

As for other apps, I use iBird Pro and Sibley Birds. Both are wonderful.

Regards and happy birding....Daniel Edelstein, Birding Guide & Avian Biologist (& College

Sunday, June 9, 2019

Warbler Guy, I seek Hermit Warbler in CA. Where shall I go? How about Black-throated Gray Warbler? Where would you take us to find these West Coast warblers?

James (in Ohio):

Good questions, with several places worth sleuthing to find your elusive, yet common wood-warbler species.

Let's focus on Marin Co.* where I live and conduct regular birding tours (* = I live 20 miles north of the Golden Gate Bridge).

First, Hermit Warbler typically nest in conifer trees such as Douglas Fir and Coastal Redwood.

Hence, these habitats are plentiful in Marin Co. (and n. CA), but the best spot I pursue for hearing AND seeing Hermit Warbler: Bolinas-Fairfax Road.

It begins in Fairfax (in central Marin Co.) and winds through beautiful, solitude-filled habitat toward the coast where it ends near Bolinas, CA.

Approximately 2 miles after the golf course on this road (as you ascend it from Fairfax), Douglas Fir habitat becomes thicker, thus attracting Hermit Warbler.

As for Black-throated Gray Warbler, I usually detect this common wood-warbler in dry forested habitat where major expanses of dense Madrone, Coast Live Oak, and CA Bay trees grow, along with other co-dominant species.

A good venue for this species: Cascade Canyon near Fairfax....or, again, Bolinas-Fairfax Road within the same Douglas Fir areas.

Feel free to let me know if you have other questions.

Always glad to help.

My birding tours to the aforementioned areas in 2019 to date yielded several views of these two wood-warbler species, I'm happy to report (and they are two of my FAVORITE wood-warbler species).

Regards, Daniel Edelstein

Birding Guide,

Avian Biologist,

College Instructor (Merritt College)


Certified Wildlife Biologist Asc.
(hosts my resume)

Saturday, May 18, 2019

Warbler Guy, I seek a high-quality binocular, but at a good price. Thoughts?

Peter (in Des Moines):

Plenty of choices, of course.

But where to start.

First, I ALWAYS sample any binocular or spotting scope before purchasing it. That's common sense.

More challenging: WHERE to find a good optics resource? What's a birder to do?

One quick fix: I have bought optics from the following online and storefront source that
features diverse choices for binoculars, spotting scopes, and optic accessories:

Out of This World Optics

The owners (Marilyn Rose and James Blackstock) provide personal service.

(They are at: 800-228-8252.....and Mendocino is a sweet, coastal town in southern Mendocino County, ~120 north of San Francisco)

Sunday, May 12, 2019

Warbler Guy, how shall I best find Kirtland's Warblers? May I take a Kirtland's Warbler tour? Tours to find Kirtland's Warblers cost?

Yes (Edith in E. Lansing), you can take a guided tour to find Kirtland's Warbler this spring and summer.


Here, you'll read details about how the U.S. Fish and Wildlife Service and Michigan Audubon Society will jointly conduct guided tours from May 15 through July 4, departing from the Ramada Inn in Grayling, Michigan. You'll need to visit the front desk upon your arrival for the meeting location. The tours will be offered on weekdays at 7:00 a.m. and on weekends and holidays at 7:00 a.m. and 11:00 a.m. Tours are free of charge.

Friday, May 3, 2019

Warbler Guy, which is the most common warbler to see in my suburban wooded backyard near Madison, WI after the peak of migration is over? In the Santa Cruz area where we have a winter home?

The answers for my peripatetic birder friend, Robert, (in Madison), are short and long.

Let’s stay with the brief ones so you can get back to birding outdoors (where I’d rather be now, truthfully (!) )

In Dane Co. where Madison lies, and depending on your yard’s habitat and its nearby vegetational makeup, you can often see Common Yellowthroat (in moist thickets and/or wetland areas where emergents occur), American Redstart (in forests), and Yellow Warbler (also most often in moist thickets and riparian areas).

As for the Santa Cruz area of California, the leading suspects during the non-breeding season (winter) include Townsend’s Warbler (a non-breeding season visitor only), Common Yellowthroat (a resident), and Yellow-rumped Warbler (non-breeding season only), with less likely visits from Hermit, Yellow-breasted Chat, Black-throated Gray, Wilson’s, and Orange-crowned, (with the latter often the most typical “winter” sighting among the final five listed above. 

Hope this helps. Now back to our regularly scheduled program, meaning I’m outta here with my binos.

(male Common Yellowthroat,
below/right; photo by
Dan Pancamo)

Monday, April 15, 2019

Warbler Guy: Where's good warbler migration sites? Do you recommend some migration birding spots to see warblers?

Good questions, Benjamin (in Seattle).

Dozens of excellent "migrant traps" for watching warblers and other songbirds exist in the lower 48 states in the USA.

I'll mention a few here: (courtesy of

There's many other excellent options beyond the ones I note below. Which ones would you add to my list?


Kennesaw Mountain National Battlefield Park, Georgia
33.91 N 84.61 W
The mile-long road to the top of the "mountain" should yield about 20 warbler species in late April. On weekends, you can ride a shuttle bus to the top. Good trails cover most of this park located about 20 miles northwest of Atlanta.

Cape May, NJ
38.56 N 74.57 W
Hawks "funnel" into Cape May each fall, making this the best spot on the East Coast for raptors. Fantastic for warblers and other migrating birds in spring and fall. One of the top 10 spots in North America.

Central Park, New York City
40.47 N 73.58 W
Birds? In New York City? During spring migration, Central Park is a welcomed island of green trees in the middle of a concrete desert. Warblers, Tanagers, Grosbeaks (and maybe a Rock Dove).

Crane Creek/Magee Marsh/Ottawa NWR
41.37 N 83.09 W
Spring migration here may be even better than Point Pelee -- and two hours closer if you live in Ohio! Go visit the Oak Openings and Irwin Prairie on the west side of Toledo as well.

Point Pelee
41.56 N 82.31 W
This tip of Ontario extends into Lake Erie, forming a welcome site for migrating birds in May and a natural "funnel" in the fall. Warblers in the spring are everywhere. Watch the flight of Monarch butterflies and huge flocks of Blue Jays in the fall. Considered by most as one of the Top 10 birding spots in North America.

Devil's Lake State Park, Wisconsin
43.42 N 89.73 W
Great scenery and a mix of northern and southern birds can be found here. For worm-eating Warbler, try nearby Baxter's Hollow Preserve. The International Crane Foundation is located just north of here in Baraboo.


As for when warbler migration begins during the spring, the range of dates vary by latitude and, often, annually, based on weather patterns.

In general (and to oversimplify), warbler migration begins in Florida in March (and becomes obvious by April) while southern Wisconsin, for example, attracts warblers in abundance by the last week of April (though it more typically peaks in the first or second week of May). Point Pelee (noted above) is often best visited during the initial days of May while upper Michigan usually peaks with warbler activity during the third and fourth weeks of May.

That's not to say warbler migration is absent prior to March in Florida or prior to May in Wisconsin. Early warbler visitors are present in both areas (e.g., LA Waterthrush in FL; Yellow-rumped and Palm Warbler in WI, among other species).

But, again, in general, warbler migration is best considered an April and May phenomenon in most lower 48 USA states.

Friday, March 29, 2019

Hi Davey....

Answer to your question, above: You can check:

....with this site a composite list featuring all the listserv sites in California.

Click on one or more as you please to see the latest bird sightings lists posted by


Glad to help:

Early arrivals in 2019 so far in Marin County (first county north of the Golden Gate Bridge in the SF Bay Area) and where many of my birding tours occur (along with Sonoma Co., a county north of Marin Co.):

- Black-headed Grosbeak (about 2 weeks earlier than most years, if this individual was a true migrant and NOT an over-wintering aberrant)

- Wilson's Warbler (heard in February this year; earlier than some years)

- Grasshopper Sparrow (~3/18 by a Sonoma Co. birder....I noticed my first ones on 3/24 and 3/25/19 at Mt. Burdell in Novato....near where I live.)

Regards, Daniel

Monday, March 18, 2019

Warbler Guy, when should I expect to begin seeing migrant-arriving Yellow-rumped Warblers?

Gus, in Wisconsin, you should expect this common wood-warbler (that nests in n. WI) to vary annually in its arrival time, given the vagaries of spring weather in the Midwest.

Generally, first migrants north of their winter range occur in the Upper Midwest by as early as late March, but greater pulses arrive beginning in early April and soon after.

At this time (often when few if any leaves are present on deciduous trees), the Myrtle subspecies of the Yellow-rumps (Setophaga cornonata coronata) may seem ubiquitous, as some birders' patience levels are tested when bird-after-bird is, AGAIN, deemed a Yellow-rumped sighting.

That's a typical scenario in WI BEFORE the initial warm, Gulf breezes occur from the south.

Then, almost like magic in the final week of April or in early May, the diverse parade of wood-warbler family members begin appearing ALONG with Yellow-rumped.

In summary:

Peak movements of Yellow-rumps in the northern US and southern Canada occur from late April through mid-May. Like many songbird species, male Yellow-rumps migrate earlier than females, averaging 4 to 7 days sooner in their arrival upon breeding grounds.

Keep in mind that some hardy Yellow-rumped Warbler individuals remain throughout the non-breeding season in the Upper Midwest, especially during warmer winters.

Wednesday, March 6, 2019

Warbler Guy, I seek a high-quality binocular, but at a good price. Thoughts?

Peter (in Des Moines):

Plenty of choices, of course.

But where to start.

First, I ALWAYS sample any binocular or spotting scope before purchasing it. That's common sense.

More challenging: WHERE to find a good optics resource? What's a birder to do?

One quick fix: I have bought optics from the following online and storefront source that
features diverse choices for binoculars, spotting scopes, and optic accessories:

Out of This World Optics

The owners (Marilyn Rose and James Blackstock) provide personal service.

(They are at: 800-228-8252.....and Mendocino is a sweet, coastal town in southern Mendocino County, ~120 north of San Francisco)

Sunday, March 3, 2019

Warbler Guy, my California bird tour means I'm looking for rare birds in California. Where do I find rare California birds on a listserv?

Hi Davey....and, "yes," and I remember you from the birding tour you invited me to lead you upon in 2012.

Answer to your question, above: You can check:

....with this site a composite list featuring all the listserv sites in California.

Click on one or more as you please to see the latest bird sightings lists posted by


Glad to help:

By the way, forget the upcoming Spring Equinox, merely 17 days away....Instead: did you know our spring actually begins in October, annually. Huh?

Yes, true: I begin hearing the courtship "peek" sound from male Anna's Hummingbirds that month. As the males descend during their courtship dance, air rushing through their tail feathers at the bottom of their elevator drop initiates the "peek" sound.

By December, eggs are in the nest in the SF Bay Area, with Great Horned Owl joining the maternity ward by January as females incubate eggs or hatch them.

Even a few Orange-crowned Warbler migrant returnees have likely already returned here, given it's 3/3/19.

I'm not one of the privileged to have yet detected them in our woodland habitats — I live and bird a lot in the Novato area where I live, 20 miles north of the Golden Gate Bridge — but I imagine a sleuthing of eBird would reveal this common breeding wood-warbler has returned in small numbers to date.

Saturday, February 9, 2019

Warbler Guy, can you help me ID these warblers? Which web site helps ID birds when I have photos?

Jessie (in Redding, CA), thanks for the photos.......To help you, please try looking at:

As for your warbler photos that you shared with me, below, here's my opinion as to their identities (from top to bottom):

Nashville, Orange-crowned, Yellow-breasted Chat

Regards, Daniel

Certified Wildlife Biologist Asc.

Avian Biologist & Birding Guide (hosts my resume)

Wednesday, January 23, 2019

Warbler Guy, can you give me a quick way to tell Myrtle from Audubon’s Yellow-rumped Warbler during the winter (non-breeding season)? I see both subspecies of Yellow-rumps where I live in the winter (SF Bay Area), so knowing how to tell Yellow-rumped Warbler subspecies apart would probably be a good idea.

Jay, in San Francisco, there’s two field marks that are excellent, diagnostic clues to help you identify both of these subspecies apart from one another (see drawings, below).

Let's sort out the "winter" plumages here only, given the obvious differences in appearance for breeding season individuals of both subspecies. 

Most (but NOT all) Audubon’s adults during the "winter" wear a faint to solid yellow throat and the Myrtle always possesses a white throat. In all age classes — from hatch year to definitive adults — a Myrtle never shows a yellow throat. That’s the easy, brief answer.

(Above drawing courtesy of National Geographic.)

But it’s not the full one. That’s because rare to occasional individuals of Audubon's ALSO may express a white throat. Which means it's possible to view a white-throated Yellow-rumped Warbler that could be EITHER the Myrtle or Audubon's subspecies.

So now what do you do for ID?

Use the absence of a faint supercilum (i.e., eyebrow) to identify Audubon’s (see drawing here) during the non-breeding "winter" season. Noticing the lack of this feature on a Yellow-rumped Warbler with a white throat should move you to say: “Bingo, it’s an Audubon’s" (i.e., Audubon's are said to wear a "plain face.)

However, if you see during the non-breeding season both a faint white supercilum mark and a white throat that reaches around toward the middle and mid-back region of the neck area on both sides of the head, then it’s a Myrtle.

In sum, Myrtle Yellow-rumped Warbler shows a faint white supercilum and a greater amount of white throat surface area than the Audubon’s subspecies that has a more plain face (lacking the white supercilium mark) and a smaller white to, more typically, faint to dark yellow throat.

The definitive source for my judgment in this matter consistently remains the Identification Guide to North American Bird, Part 1, by Peter Pyle (Slate Creek Press), which is the bird bander's guide to identification of birds "in the hand," and features field mark information corresponding to all age classes of songbirds.

Saturday, January 5, 2019

Warbler Quiz #16...Can You Name These Warblers, Below?

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

Check back by 1/19/19 for the answers....or email me at

(See "Birding Links" pulldown menu for birding information)

Regards, Daniel

Freelance Avian Biologist

Birding Guide