Colima Warbler Leiothlypis crissalis

Rather drab warbler of highlands in Mexico. Dusky gray-brown overall with grayer head, bold white eyering, buffy flanks, and mustard-yellow undertail coverts. Sings from atop bushes and small trees, but otherwise rather skulking, generally staying low and well-hidden. Does not join mixed-species flocks. Breeds in oak scrub and thickets within mountainous pine-oak forest. Winters in brushy flower banks and tangles within pine-oak forest. Breeding range barely enters the U.S. in the Big Bend region of Texas.