Black-capped VireoVireo atricapilla
Flitting about actively in the oak scrub, often hanging upside down momentarily, the little Black-cap is our most distinctive vireo. It is also the rarest, nesting only locally in Texas and Oklahoma. Its eggs take an unfortunately long time to hatch; cowbird eggs, laid in the same nests, usually hatch first, so that the vireos raise only young cowbirds. Without some kind of control of cowbird numbers, the vireo may face extinction.