A young black-throated gray warbler visited a feeder in Taunton, MA for about three weeks in January, 2013 until temperatures dropped into the teens and single digits for several days.
The Black-throated Gray Warbler is considered a short-distance migrant, moving from its breeding areas in the western United States only as far south as Mexico. Typically found west of the Rockies, these warblers follow mountain ranges and the Pacific coastline as they migrate southward. Despite these landmarks, however, some get lost. A few turn up every year in the eastern states as vagrants.
On determining the age and sex of this bird Marshall Iliff writes:
I strongly feel this bird is a first-winter (SY) male. The black ear coverts should make it a male, since females should all have grayish ear coverts. Adult males should have entirely black crowns and black throats extending to the chin and touching the base of the mandible. Since this bird has gray in the crown, a white chin, and a black throat that is partly veiled by the white tips to the throat feathers (giving the throat a white look at some angles, and fully black throat at others, especially from below), I think it cannot be an adult male. Adult males at most have very narrow white fringes to the throat in fresh plumage, and I'd expect these to be worn away at this point, making the throat entirely black at any angle. Since first-winter females are entirely white throated, this is sure to be a hatch-year male.
The biggest concern is eliminated adult female, but the dark ear coverts should help with this. I believe that the rectrix shape (slightly pointed) may also support the age as SY, but we may need better photos to be confident of this.
This of course matches my assumptions, since the vast majority (90%+?) of vagrant landbirds like this are hatch-year birds.
© Garry Kessler