First of all, it's a good custom to write your name..at this point I have
no idea who I am communicating with and even though the internet is
impersonal, I would rather know I am talking to a real person!
The White-crowned Sparrows can be separated; there is a pretty good account
in the NGS guide. But in summer, the only one we have around here in the Bay
Area (usually within the fog line, the moister and cooler areas of the Bay)
is the Nuttall's. In September the Gambel's and Puget Sound birds come down,
then it becomes tougher. Nuttall's and Puget Sound are often inseparable in
the field; Gambel's is more straight forward if you look carefully.
North Americans tend to follow the AOU list, and they have not voted on the
Yellow-rumped Warbler now that new information has come out on them. Of the
four possible species, two are found south of the border and are resident.
The Audubon's - Myrtle pair is treated in the major field guides, or for
more detail Dunn and Garrett's Warbler Guide (part of the Peterson Series)
is good. The separation of these two birds can be tough in winter,
particularly young birds. The general bits to look for are 1) yellow on
throat = Audubon's 2) Big white wing patch = Audubon's 3) Dark mask, and
obvious pale supercilium = Myrtle 4) Face and throat colors blend rather
than change more drastically = Audubon's 5) more white in tail = Audubon's
Half Moon Bay, California
Field Guides - Birding Tours Worldwide
From: SFBirds@... [mailto:SFBirds@...] On Behalf Of
Sent: Friday, July 09, 2010 5:52 PM
Subject: [SFBirds] Can the experts help?
I have two questions for any of the experts who can help:
1. How can you identify the subspecies of a white-crowned sparrow? A pair
visited my yard. One had an extended bath in the birdbath; the other foraged
enthusiastically amid the Mexican daisies. Is there any way of telling
whether they're Nutall's or one of the others?
2. On the yellow-rumped warblers: I find IOC has split them into 4 species,
but AOU hasn't. How do most birders on this list treat them? (And how do you
distinguish an Audubon's and a Myrtle?)
Many thanks to anyone who responds.