The black-capped vireo (''Vireo atricapilla'') is a small

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

native to the United States and Mexico. It was listed as an

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

in the United States in 1987. Successful conservation efforts on the U.S. Army's Fort Hood and

Fort Sill Fort Sill is a United States Army post north of Lawton, Oklahoma, about 85 miles (136.8 km) southwest of Oklahoma City. It covers almost . The fort was first built during the Indian Wars. It is designated as a National Historic Landmark ...

led to delisting the black-capped vireo in 2018. The

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

lists the species as vulnerable.

Description

The black-capped vireo is a songbird about 12 cm (4.5 inches ) 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 often have more extensive gray in the cap, similar to adult females.

Nesting

The male and female in a pair assist in nest construction and incubation. Typically, the female lays three or four eggs. The incubation period is 14 to 17 days, and the nestling period is 10 to 12 days. The female broods over the young, while the male supplies most of the food during the nestling phase. 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 nests again, sometimes with another male. These birds are insectivorous, with

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

s and

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sym ...

s making up a large part of their diet. Black-capped vireos nest in "shinneries", brushy areas with scattered trees. Shinneries primarily consist of shin oak or sumac. Appropriate height and density are important factors for this species' breeding success. Foliage that extends to ground level is the most important requirement for nesting. Most nests are between 15 and 50 in (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, the preferred black-capped vireo habitat is a mixture of shrubs and smaller trees that average from 8-10 ft high (2.5-3.5 m). Black-capped vireos stop using sites where many trees are nearing full size.

Distribution

The historic breeding distribution of the black-capped vireo extended south from south-central

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...

through central

Oklahoma Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...

and

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

to central

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

. At present, the range extends from Oklahoma south through the

Edwards Plateau The Edwards Plateau is a geographic region at the crossroads of Central Texas, Central, South Texas, South, and West Texas. It is bounded by the Balcones Fault to the south and east, the Llano Uplift and the Llano Estacado to the north, and the ...

and

Big Bend National Park Big Bend National Park is an American national park located in West Texas, bordering Mexico. The park has national significance as the largest protected area of Chihuahuan Desert topography and ecology in the United States, and was named after ...

, Texas, to at least the Sierra Madera in central Coahuila, Mexico. In Oklahoma, the black-capped vireo is found only in Blaine, Cleveland, Cotton and Comanche Counties. The winter range of this vireo is not well known. It is thought to winter along the west coast of Mexico from southern

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...

to Guerrero.

Conservation

The black-capped vireo is threatened by brown-headed cowbird (''Molothrus ater'') brood parasitism, human disturbance, and loss of habitat to urbanization, fire exclusion, grazing, and brush control. With population sizes now well into the tens of thousands, the species continues to be managed by the Texas Parks and Wildlife Department and the Oklahoma Department of Conservation. Conservation efforts by the U.S. Army are continuing to enhance the conservation status of the black-capped vireo.

References

External links