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Listed as an endangered species in October of 1987, the black-capped vireo (Vireo atricapilla) is a
neotropical (of the New World Tropics) migratory songbird. Their original breeding range extended
from central Kansas south through Oklahoma and Texas and into northern Mexico. Habitat loss has
reduced their breeding range to predominantly central and southwest Texas though they may still
possibly occur in small portions of Oklahoma and Mexico. These birds migrate to the western
coast of Mexico for the winter.
These insectivorous birds are on average 4.5 inches long. Mature males are an olive green on
their back, white on their belly, and a slight yellow green on their flank above their leg.
The species name comes from the black color on the top and sides of their head. The female
coloring is similar but duller than the male with a grey head in place of black. Both sexes
have a black beak and a brownish-red iris, but differ in the coloring around the eyes. Males
have a partial white eye ring while the eye ring on females is black.
Although the habitat can be highly variable in some components such as plant species, soils,
temperature, and rainfall, it is consistent in having a patchy "look". Woody species are shrubs that
are between four and six feet high, are broadleaved and thick, and extend to the ground to hide and
protect nests only a few feet from the ground from predators. The shrubs cover about half of the
overall habitat area but are spread out and interspersed with open grassy, meadows or areas of bare
rock in a patchwork. In central Texas, this type of habitat is often a result of regrowth after the
occurrence of clearing, overgrazing or fire.
As migrants, these birds spend only their breeding season in our area, arriving between mid-March
and mid-April and leaving between mid-August and mid-September. Males establish and defend
territories, though several territories are often clustered within appropriate habitat. Both
parents select and build the cup-shaped nest suspended from a fork of two or more branches
deep within the thicket. Either both parents attend to the young or one assumes the role;
or they may split the responsibility for a large brood. They are capable of having more than
one brood during a breeding season, though this species is often targeted by nest-parasitizing
brown-headed cowbirds which greatly reduce their overall productivity.
In addition to the brown-headed cowbird, these birds face several challenges for survival today.
Natural plant succession can change their preferred habitat into woodland, resulting in loss of
habitat for them. Outright loss of habitat occurs as a result of clearing, over browsing by
deer or domestic animals, and fire suppression. In the latter case, fire in pre-settlement
times was important for maintaining shrubs and reducing woodlands making prescribed fire an
important management tool for restoration of vireo habitat. Conservation of their wintering
habitat must also occur to ensure survival.
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