Status: Endangered (54 FR 37420; October 6, 1987). Critical habitat has not been designated.
Description: The black-capped vireo is a songbird about 4.5 inches (12 cm) in length. Sexually mature males are
olive green above and white below with faint yellow flanks. The crown and upper half of the head is black with a partial white
eye-ring and lores. The iris is brownish-red and the bill is black. Females are duller in color than males and have a slate gray
crown and underparts washed with greenish yellow. First year males are intermediate in coloration between adult males and
females.
Life History: The male and female in a pair assist in nest construction and incubation. The female broods the
young, while the male supplies most of the food during the nestling phase. Typically, three or four eggs are laid. The
incubation period is 14 to 17 days, and the nestling period is 10 to 12 days. Breeding pairs are capable of producing more
than one clutch per breeding season. The male cares for some or all of the fledglings, while the female re-nests - sometimes
with another male. These birds are insectivorous, with beetles and caterpillars making up a large part of the diet.
Habitat: Black-capped vireo habitat consists of scattered trees and brushy areas. The presence of oak
trees appears to be more important to the vireo than junipers. Foliage that extends to ground level is the most important
requirement for nesting. Most nests are between 15 and 50 inches (35-125 cm) above ground level and are screened
from view by foliage. Territories are sometimes located on steep slopes, where trees are often clumped and intermediate
in height. On level terrain, preferred black-capped vireo habitat is a mixture of shrubs and smaller trees that average from
eight to 10 feet high (2.5-3.5 m). Black-capped vireos will no longer use sites where many trees are nearing full size.
Distribution: The historic breeding distribution of the black-capped vireo extended south from south-central
Kansas through central Oklahoma and Texas to central Coahuila, Mexico. At present, the range extends from Oklahoma
south through the Edwards Plateau and Big Bend National Park, Texas, to at least the Sierra Madera in central Coahuila,
Mexico. In Oklahoma, the black-capped vireo is found only in Blaine, Cleveland, and Comanche counties. The
winter range of the black-capped vireo is not well known. It is thought to winter along the west coast of Mexico from
southern Sonora to Guerrero.
Causes of Decline: The black-capped vireo is threatened by brown-headed cowbird (Molothrus ater)
nest parasitism, human disturbance, and loss of habitat to urbanization, fire exclusion, grazing, and brush control.
Recovery Needs: The top recovery tasks for the black-capped vireo include: 1) determining where cowbirds
pose a threat and controlling their numbers in vireo breeding areas; 2) determining threats to vireo winter habitat; and 3)
determining how to manage habitat for the vireo.
Other information: Ongoing projects in Texas and Oklahoma to recover the black-capped vireo include extensive
cowbird trapping and cowbird egg removal from nests. Studies on the nesting ecology and population dynamics of the
black-capped vireo are also contributing to our understanding of the species.
