Wednesday, December 18, 2013

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 white 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.

Tuesday, December 10, 2013

Warbler Guy, I'm coming to California birding tour soon, so where do I check for "rare" bird alerts? Do you remember leading me as a birding guide when we went to Point Reyes National Seashore?

Hi Davey....and, "yes," I remember you from our birding tour 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:

Happy Holidays and, remember, only ~45 days until our first neotropical migrant
returns to the SF Bay Area for the nesting season:
Allen's Hummingbird

Darn, though: Orange-crowned Warbler returnees are still ~50 to 60 days from appearing after migrating here.

Sunday, December 1, 2013

Warbler Guy, which app for iPhone & my phone, an Android, works to see Ebird sightings? Can I see where to go for Ebird sightings by using a bird app?

Carly, in Portland:

I've pasted the best app I know as the solution to your questions, above.

Though I don't remember the price I paid for Birdseye, it's an app I utilize frequently.

Any time I wish to know where the latest-greatest bird sightings have been in my area (or to any area that I travel, near or far), I look at Birdseye on my iPhone 5.

Happy Holidays, Daniel

415-382-1827 (SF Bay Area)

Wednesday, November 13, 2013

Warbler Guy, what about the Peterson Guide To Birds app? How is this app good for warblers? Other bird species?

Gloria, I've pasted a couple of excellent screen shots below for you to see how this amazing app features wonderful color plate drawings.

The warbler ones are equally impressive (though I did not share any here).

Plus, there's oodles of features on this app to use in the field and among your friends (if you all get it) that lead me to provide an "A" grade for this app.

Yes, I have it...and, yes, it was given to me (full disclosure!), but I'd also buy it, if necessary, at the iTunes Store.

Thumbs up from me.

To find it.....

Type in at the iTunes Store:

Peterson Birds


Peterson Guide To Birds

Best wishes, Daniel

Thursday, November 7, 2013

Warbler Guy, I know you're into the little birds, but you seem to live near recent Blue-Footed Booby observations in Marin County, correct? Have you seen the booby at Gull Rock like I read about on Rare Bird Alerts?

Yes, Germaine (in Seattle): I have led some bird tours there recently and, indeed, here's a photo from Isaac Sanchez on 11/5/13 when I served as his guide for the day.

Every time I've been to Gull Rock, one or two immature/sub-adult Blue-footed have been present FAR AWAY.

Thus, this photo is obviously a booby, but it's from at least .5 mile away.

Hope this helps you. Regards, Daniel
415-382-1827 (O)

Friday, November 1, 2013

Warbler Guy, how many Kirtland's Warbler individuals hatched this year? Do Kirtland's Warblers face extinction?

Roy, in Racine, WI, here's a "copy & paste" from a fine email newsletter published by Wayne Peterson & Paul Baicich (via:, noting the 2013 breeding success of Kirtland's Warbler in Michigan, Wisconsin & Ontario:

(Before you read it, did you know Kirtland's Warbler has nested in Wisconsin for seven consecutive breeding seasons? More about the federally endangered Kirtland's Warbler in WI can be read at the WI DNR link provided on the last lines, below.)

(photo courtesy of Wikipedia Commons,


The numbers from the last breeding season are officially in, and Kirtland's Warblers remain near an all-time high.

The Kirtland's Warbler survey is annually conducted by the U.S. Fish and Wildlife Service, U.S. Forest Service, Michigan DNR, Michigan Department of Military and Veterans Affairs, Michigan Audubon Society, and numerous citizen volunteers. Kirtland's Warblers nest on the ground in central Michigan, various counties in Wisconsin, and in Ontario where they usually select nesting sites in stands of jack pine between four and 20 years old. Surveyors seek out singing males on territory to identify this species during the breeding season.

Biologists, researchers and volunteers observed 2,004 singing males in Michigan during the official 2013 nesting survey period. An additional 21 singing males were found outside Michigan, in Wisconsin (18) and in Ontario (3).

In 2012, there were 2,063 singing males counted in Michigan. These numbers are in stark contrast to those of 1974 and 1987, when only 167 singing males were found - the lowest survey numbers ever recorded.

The current revival has been so impressive that removing the species from the federal Endangered Species list is a possibility, perhaps some time in the near future.

"Two thousand pairs of birds is still a pretty low number," warned Philip Huber, a U.S. Forest Service biologist working on the project. Because Kirtland's Warblers are so uniquely adapted to a sandy-soil jack-pine habitat, they now depend heavily on human intervention for survival (e.g., cowbird removal, pine-plantings, and fire-management).

"Our success is allowing managers to work with additional partners to transition from a mode of recovery to one of long-term sustainability," said Dan Kennedy, Michigan's DNR endangered species coordinator.

For more information about this rare bird, visit the Michigan DNR's Kirtland's Warbler web page:

For Wisconsin's Kirtland's Warbler web page:

Thursday, October 24, 2013

Warbler Guy, have Dusky Warbler and Arctic Warbler ever been seen in California?

(above, Arctic Warbler, via

Joey (in New York, NY), at least 10 accepted California records exist for the Dusky Warbler, per the judgment of the California Bird Records Committee. The same committee has agreed that at least four past Arctic Warbler sightings are valid.

A good book to obtain for “hovering and gleaning” this information:

Rare Birds of California. 2007. Western Field Ornithologists. See:

(Updates for new accepted records are online at:

Wednesday, October 16, 2013

Warbler Guy, I think I just saw an Orange-crowned Warbler (OCWA) in my yard here in S. Carolina. Is that possible (on October 15, 2013)? Migrating warblers includes Orange-crowned to the East? Orange-crowned remain in the East during the fall-winter?

Josie, indeed, please see the map, below, given the non-breeding season range in ORANGE COLOR, below) from the Field Guide To The Warblers (Jon Dunn and Kimball Garrett, Houghton-Mifflin, 1997), it’s likely your ID was correct. (Please email me and I'll send you a PDF of the OCWA range map that shows its non-breeding season presence in the East/Southeast USA....I will upload this map soon here. My email: danieledelstein at att dot net (You need to type the @ symbol and dot, of course.))

Kudos on you.

Correct me if I’m wrong, readers, but I also have seen OCWA during even later periods (Nov. – Jan.) in the East, including MD and it sometimes lingers (and/or overwinters?) into the late fall (and winter?) within the mid-Atlantic and lower N.E. states, based on my experience of living in the East long ago.
(Please feel free to make a “comment,” below, readers, relating to this issue...I’d appreciate feedback.)

(Map, below, via Birds of North American Online, per:

Gilbert, W. M., M. K. Sogge and C. Van Riper III. 2010. Orange-crowned Warbler (Oreothlypiscelata), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online:

Monday, September 30, 2013

Why are Yellow-rumped Warbler so common to see in fall migration?

Joan (in Boston):

Here's why you see Yellow-Rumped Warbler in many different habitats and, especially, en masse during a prolonged spring and autumn migration (in the Midwest and East):

1. Among the four subspecies in the Yellow-Rumped Warbler (YRWA) species, one is the Audubon subspecies (including the male Audubon YRWA seen in the above photo). 

2. YRWA exploit multiple feeding niches within the profile of the forest. That is, you are as apt to see them in the interior branches near the main trunk as you are to notice them near the ground. As a “hover and gleaner” feeder (like many Dendroica genus wood-warbler members of which the YRWA is enrolled), you can expect to see YRWA in a forest profile, but they also might be at the seashore (finding invertebrates near the surf) or, even, on grassy lawns (where insects may provide food resources). 

3. In turn, given YRWA is able to exploit multiple environments and feed on diverse food resources – from insects, to fruit (such as poison oak and poison ivy berries, in addition to privet and wax myrtle berries – the species is well-adapted to sustaining its populations in times of food scarcity. That is to say, the YRWA has a diversified portfolio – a perfect tactic to ensure that the boom and bust of food resources does not impact the species’ numbers.

4. The hydrochloric acid content within YRWA individuals appears to be more potent than the digesting apparatus contained within most other wood-warblers. In fact, the wax myrtle berries that help YRWA survive harsh conditions in winter along the mid-Atlantic are not digestible by most birds, including the 51 other wood-warbler family members typically found annually in North America north of Mexico. Given the abundance of wax myrtle, YRWA are able to survive into the deep fall (and sometimes throughout the winter) in states that often encounter harsh winter conditions: WI, MI, OH and, in the East, MD, VI, NY (and in some New England states during some winters). 

Seeing YRWA in November and December, thus, is not uncommon in the states mentioned immediately above. Increasingly warmer winter seasons, too, provide succor to YRWA that do not need to vacate northern latitudes as is the custom in the vast majority of other songbirds.

(Note: This article originally appeared at this blog in a similar form, but I receive periodic queries about this question as answered above, so I decided to post this article again, given Yellow-rumped is annually common throughout northern latitudes in late September/October.)

Thursday, September 26, 2013

Sound Answer?: Can you identify the warbler singing in the background?....

.....and if you go to:

Listen to the 2nd version of the Nuttall's Woodpecker from the top of the page*.

Which warbler is singing in between call notes of the woodpecker?

(* = The 1:01 recording is from the work of Thomas C. Graves.)

Hint: It's an early arrival in central and northern California, with migrants arriving
as early as the first week of February some years.

If you seek the answer, please email me and I'll reveal it:
(The subject of the answer is shown below.)

Meanwhile, I have a San Francisco bird tour soon, so I am getting ready to leave...and, hence, will do the same here. Enjoy. DE.

Sunday, September 15, 2013

Warbler Guy, now that the leaves are starting to fall in my northern locale, I found a couple of warbler nests. Hence, is there a newer bird nest field guide than the great, yet limited Hal Harrison East & West Coast bird nest books?A Guide to the Nests, Eggs, and Nestlings of N. American Birds. Paul J. Baicich & Colin J.O. Harrison, Academic Press, 1997, 2nd edition

Sherry, you are in luck, given the following recent 2011 publication Nests: Fifty Nests and the Birds That Built Them (Chronicle Books). In it, Sharon Beals features amazing photos of USA bird species, including the one shown here: Golden-winged Warbler (which, by the way, is a Watch List* species according to the National Audubon Society, meaning it's numbers appear to be decreasing in portions of its breeding range, per census figures).

(* = See

So, start your Nest Search Engines, people (and Sherry), as this species would truly be a jewel to find.....and I am lucky to note that I saw one migrating Golden-winged recently in Wisconsin
during a birding trip to find warblers and other avian migrants.

Meanwhile, the Harrison guides round out my nest library of, along with A Guide to the Nests, Eggs, and Nestlings of N. American Birds (Paul J. Baicich & Colin J.O. Harrison, Academic Press, 1997, 2nd edition)

Saturday, August 31, 2013

Warbler Guy, does the new American Birding Association "Birder's Guide" magazine have articles about wood-warblers?

Good question, Tom R. (in Seattle).

I'm confident the answer will eventually be an ongoing "yes," though I have the premiere issue of this new magazine and, gulp, I feel deprived because no mention of wood-warblers occurred among the excellent initial articles.

No doubt, the rising popularity of birders pursuing wood-warblers nationwide means this new periodical (that replaces the now-defunct Winging It ABA publication) promises to be a wonderful source for The Warbler Guy and you to read about worthy wood-warbler birding places.

Here's a review of Birder's Guide as it appears on the web site:

Birder's Guide is the new, quarterly, full-color ABA magazine. Instead of 96 pages of black-and-white content appearing in your mailbox each year (Winging It), you'll now receive about 192 pages of a full-color, glossy magazine—on top of the 6 issues of Birding you already get! And that doesn't include the expanded online content we have up our sleeves.
Our first issue, A Birder's Guide to Travel, is, well, precisely that! Within its pages you will find practical, useful tips from experienced travelers on what technologies can make your trip most productive, on how and what to pack, and, most importantly, on where and when to go, and why. Making a reappearance is the ABA's much-valued Pelagic Directory, which had been on hiatus the past two years. ABA members will receive two more issues ofBirder's Guide later this year: A Birder's Guide to Listing and Taxonomy and A Birder's Guide to Gear. We’re trilled to offer the first (and all subsequent issues of) Birder’s Guide as a downloadable e-magazine, available at the following link:

Monday, August 19, 2013

Any common bird name changes to the annual American Ornithological Union (AOU) Check-List, Warbler Guy? In turn, does the American Birding Association (ABA) adopt these new bird name changes, including splits that create two new species?

Jake, that's a great question.
The recently published July issue of The Auk (published by the AOU) has the answer. 

It features the annual supplement to the AOU Check-List*, and, indeed, the ABA Checklist automatically adopts changes in taxonomy adopted by the AOU.
(* = Fifty-Fourth Supplement to the American Ornithologists’ Union Check-list of North American Birds(pp. 558-571)  
R. Terry Chesser, Richard C. Banks, F. Keith Barker, Carla Cicero, Jon L. Dunn, Andrew W. Kratter, Irby J. Lovette, Pamela C. Rasmussen, J. V. Remsen Jr., James D. Rising, Douglas F. Stotz and Kevin Winker)

But do NOT get too excited. Sit back in your chair. The ONLY new landbird split for the entire 2013 list centers on the SAGE SPARROW. It's a GREAT, handsome bird species, no doubt. 

The newly split Bell's Sparrow, this one from Baja California, Mexico, photo by Jorge Montejo via flickr

BUT not a wood-warbler. 

So, ho-hum, here are the details on the split: The old, you're-sooooo 2012 version of the SAGE SPARROW
is now the Sagebrush Sparrow (Artemisiospiza nevadensis) and Bell’s Sparrow (Artemisiospiza belli).

The Bell's species includes the intermediate-looking, interior-California-breeding subspecies called canescens as the scientific name trinomial. Some experts believe this population may eventually be split from Bell’s Sparrow and become a species of its own. Most if not all vagrant records of “Sage Sparrow” in the central and eastern parts of North America relate to Sagebrush Sparrow.

OK, now back to the edge of your chair and out the door with your binoculars as you enjoy the southbound wood-warbler migration. Pinch me, as I'll soon enjoy seven days in WI while searching for wood-warbler dispersers and migrants as I head to the Milwaukee, Ozaukee, and Door County area for birding by myself and with friends.

(Err, I must admit, some day soon, I'll again be able to lead tours there in the spring and fall....For now, it's a mere personal foray and no tours or classes scheduled, BUT feel free to tempt me by contacting me, if you wish: danieledelstein at att dot net....and warblerwatch dot com)

Thanks to the ABA's Michael Retter who helped me read and learn about the aforementioned split. He's a treasure and his writing is easily found at the ABA birding blog: