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Saturday, September 01, 2012

Fall Warbler ID Quiz answers

Mystery Warbler 1 is a Pine Warbler

Mystery Warbler 2 is a Yellow-rumped Warbler

Mystery Warbler 3 is a Black-throated Green Warbler

Yesterday we posted a quiz of these fall warblers that we saw yesterday on our property in southwest NH. Above are the answers. Good for all of you who guessed. The first person to get the right answers was Jim Royer of Los Osos, CA. Congratulations to Jim, especially since these warblers are more usual in the East, not CA (except for Yellow-rumped Warbler, but we have the eastern subspecies in the East, he sees the western subspecies in CA.)

The first mystery warbler is a Pine Warbler in very dull plumage, most likely a 1st yr. female. Looks very like the photo in our The Stokes Field Guide to Birds of North America, page 618. This bird has none of the yellow coloring so prominent on the breast and head of the adult male and on the breast of the adult female. This bird could be confused with the similar winter Blackpoll Warbler which has a streaked back, neck color not extending around dark ear patch, white tips to primaries, brighter white wingbars, pale yellow or pinkish legs with bright yellow soles of feet, tail extending less beyond undertail coverts. Also you must rule out the winter Bay-breasted Warbler which often has a hint of pale chestnut on flanks, some back streaking, buffy undertail coverts and dark legs.

The second bird is a very molting looking Yellow-rumped Warbler, which looks more orangish yellowish on the sides on this individual. Typically they have yellow on the sides, a good clue even when you cannot see the yellow rump. Very pale fall Yellow-rumps, usually first year females, may even lack the yellow on the sides. The similar winter Palm Warbler has a yellowish rump but bright yellow undertail coverts and pumps its tail. Similar winter Magnolia Warbler has yellow rump but is yellow below, similar winter Cape May Warbler has greenish-yellow rump.

The third warbler gives a little more color to help identify it, although, this is more typically the kind of look we get at warblers, a bird hidden behind foliage! The yellow face is noticeable and there are hints of black on the throat and sides of upper chest and noticeable black streaks on the sides. In winter, Black-throated Green males can have their black throat veiled with white, so the black is not as dramatic as in summer. The female has even more white on the throat, and blurry side streaks. First winter birds are even paler. I like the way the yellow on the vent is obvious in this photo, all ages and sexes of Black-throated green have this yellow there, a good clue.

Fall warbler migration is just beginning. To learn more about warblers, see our new best-seller, The Stokes Field Guide to the Birds of North America and look closely at the warbler section which shows  all the fall plumages of the warblers.

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