Sunday, February 7, 2010
Warbler Guy, Help Me?: I’m in Florida and wondering if the photos here are western or eastern subspecies of Palm Warbler?
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.”