Wednesday, January 18, 2017

Warbler Guy, how do I know if warbler migration is strong? Migrating warblers are more dense on some spring days than other ones?

One that is good: Birdcast


At this link, you'll read about the current week's presence of migrators and predictions.

It is a great resource, given the BirdCast forecast highlights migrant species that you can expect to see in each of several regions: Upper Midwest and Northeast; Gulf Coast and Southeast; Great Plains; and West. 

Saturday, January 7, 2017

Warbler Guy, what’s an example of a “superspecies” in the wood-warbler family?

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

(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).

Thursday, December 15, 2016

Warbler Guy, given I live in the SF Bay Area, which warbler species are the most common to see during the non-breeding season (i.e., overwintering species)?

Good question, Sheehi (in Fairfield).

In general, in correct habitat, below I list the order (from most common to rarest) for abundance of wood-warbler species in the SF Bay Area during the non-breeding season. I suggest only the initial two on the following list — Yellow-rumped and Common Yellowthroat — are common to detect throughout the SF Bay Area during the non-breeding season:

(Orange-crowned Warbler, above, a common SF Bay breeding species, but rare to absent during the non-breeding season)

1. Yellow-rumped Warbler

2. Common Yellowthroat

3. Depending on which habitat you visit, the next most common species to detect could be:

Orange-crowned Warbler (strongest contender for the 3rd spot; see above photo)
Hermit Warbler (rare to absent during the non-breeding season)
Wilson's Warbler (rare to absent during the non-breeding season)
Palm Warbler (seen annually during the non-breeding months, but never common in the SF Bay
Area during the "winter" months.....most common seen in during autumn migration along the coast, especially within Point Reyes National Seashore)
Black-throated Gray Warbler (rare, but annually seen during the winter, and, if so, during the West Marin Christmas Bird Count, for example)
Nashville Warbler (rare to absent during the non-breeding season; typically a transient in the SF Bay Area; does not nest here)

Regards, Daniel
(hosts information about my 25+ years of Wildlife Biology services, in addition to my bird tours via the "Bird Tours" tab)

Wednesday, December 7, 2016

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

Sunday, January 17, 2010

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

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):

(By the way, my Web site,, features a button -- "2016 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 sometimes extract one from the landscape.

The Stinson Beach area is another "hot spot" for periodic sightings of uncommon overwintering/non-breeding season warblers, with NASHVILLE WARBLER and HERMIT WARBLER seen there on 12/5/16 by Peter Pyle. Check out under his North Bay Birds listserv post, if you wish directions to the grove of trees where he saw these two species (as I know it's often a prime spot to watch for warblers in December/January annually).

Regards, Daniel
(features my "Birding Tours" information for the 8-hour trips I often lead for birders)

Sunday, November 20, 2016

Answer to 11/3/16 quiz, below: Orange-crowned Warbler

....and thanks to those who responded....Several were correct!: Orange-Crowned Warbler (subspecies celata) (Oreothylpis celata celata) (Photo credit: Arlene Ripley)

Thursday, November 3, 2016

Quick Quiz: Which wood-warbler is this one (in the photos)?

My friend Jim McGinity in Florida is an excellent birder and bander who temporarily captured this beauty recently......along with these fine photos.

Any guesses as to which species? -- per adding a "comment" below. I'll post the answer in a wee here.

Regards and happy birding, Daniel

Wednesday, October 19, 2016

Warbler Guy, do you have any advice for IDing "confusing fall warblers?"

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:

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 autumn birding!