The Black-capped Vireo is a dapper-looking small bird with a dark head set off by white lores and eye ring, giving it a spectacled appearance. The bird’s red eyes are also distinctive. It is a habitat specialist, preferring areas that have been recently burned; periodic fire halts the spread of invasive junipers and enhances growth of the oak scrub that they prefer.
Populations of Black-capped Vireos are small, fragmented, and declining. The species was listed as Endangered under the Endangered Species Act in 1987. Fire suppression is probably the most serious threat to this bird, but urban development and agricultural conversion (especially to pasture) have caused significant habitat loss. Nest parasitism by the Brown-headed Cowbird may affect up to 90% of nests in an area. Nestlings are sometimes killed by fire ants.
Cowbird control is an essential conservation measure for the species, as are prescribed burns and fire ant control. These measures are in place at several important sites for the vireo, such as Fort Hood Military Installation, Balcones Canyonlands National Wildlife Refuge, and Kerr Wildlife Management Area. These measures have in some cases resulted in dramatic increases in the vireo’s numbers. More information is still needed on this vireo’s distribution and abundance in Mexico.