Family: Vireonidae, Vireos view all from this family

Description 4 1/2 -4 3/4" (11-12 cm). Smaller than a sparrow. Olive green above, white below; crown and sides of head glossy black; white "spectacles." Female similar, but crown and sides of head slate-gray.

Endangered Status The Black-capped Vireo is on the U.S. Endangered Species List. It is classified as endangered throughout its range in Kansas, Louisiana, Oklahoma, and Texas. In recent years this vireo has become rare, mainly because its nesting has been disrupted by cowbirds. These notorious nest parasites remove eggs from a vireo's nest and deposit their own eggs in their place. The young cowbirds are so much larger than the host bird's young that they crowd and starve them out. The loss and alteration of its habitat, mainly by humans, has also affected this species. Programs are underway in Texas and Oklahoma to prevent cowbird parasitism, by trapping the birds and removing their eggs from other birds' nests.

Habitat Dense oak scrub and juniper thickets.

Nesting 4 unspotted white eggs in a well-made pendant cup of plant fibers and bark strips decorated with lichens and concealed in a shrub or bush.

Range Breeds from Kansas south through Oklahoma to central Texas. Winters in Mexico.

Voice Harsh and varied phrases, sometimes musical.

Discussion This little vireo, with its restricted range, differs from most vireos in being rather nervous and active-more like a warbler in its behavior. It is a tireless singer but is often difficult to find in the dense oak scrub. It has a titmouse-like habit of hanging upside down while foraging among twigs.