Black-capped Vireo

Vireo atricapilla

Image by Texas Parks & Wildlife Department
  • VIREONIDAE
  • Vireos
  • Passeriformes
  • Vireo de gorra negra
  • Viréo à tête noire
Introduction

The smallest vireo in the United States, the Black-capped Vireo is a colorful songbird, whose closest relative is the Mexican Dwarf Vireo. Avid songsters, the male even sings while incubating eggs and catching food. Listed as Endangered since 1987, U.S. populations still appear to be declining overall, including range losses in Kansas and Oklahoma. Some managed populations in Texas have increased significantly, and some new populations have been discovered in Mexico.

Bird Sounds
Lang Elliot
Appearance Description

The common name for this warbler-sized vireo appropriately describes the adult male. He sports a black cap and has white "spectacles" that are interrupted with black above the eye. The back is olive green, and underparts are mostly white with olive- and yellow-tinged flanks. The wings and back are dark olive to blackish with two pale yellow wingbars. The iris is red to reddish brown. Females and juveniles are similar to males but have a gray cap and a brown iris. The song is a very complex assemblage of vireo-type phrases; however, this species has a repertoire that is perhaps five to 10 times more diverse than that of other vireos. The Black-capped Vireo measures about 4.5 inches long with a 7-inch wingspan and weighs .3 ounces.

Range Map
Courtesy Kenn Kaufman
Range Distribution

Formerly widespread from Mexico to Kansas, this vireo is now confined as a breeder to 38 counties in Texas, three counties in Oklahoma, and three states in Mexico, from Coahuila, through Nuevo Leon, into southwestern Tamaulipas, where a small but significant breeding population was reported in 2005. The highest concentrations in summer appear to occur in Texas, probably on Fort Hood. The wintering range is a narrow band along Mexico's Pacific Coast. It starts in far southern Sonora State and extends south into coastal Oaxaca, with the widest distribution from Nayarit to Michoacan.

Global-level Important Bird Areas in Mexico that have been identified as supporting breeding populations of the species include Sierra Maderas del Carmen IBA, Sierra del Burro IBA, Nacimiento Rio Sabinas/ SE Sierra de Santa Rosa IBA, and Presa el Tulillo IBA.

Habitat

In the breeding season, the Black-capped Vireo prefers arid scrub and brush lands with a complex mixture of vegetation close to the ground, both short and tall shrubs, and open spaces. This habitat is rare and localized in gullies, ravines and eroded slopes. Breeding territories range between 2.5 and 25 acres and can overlap with White-eyed Vireo (V. griseus) territories. The White-eyeds seem to prefer the brushier gullies and the Black-cappeds prefer the more open areas on slopes and hilltops. Typical plants in this habitat include dogwood, junipers, various scrubby oaks like the shin oak, sumac, and Texas persimmon. Frequent natural fire produces the best conditions. Wintering and migrating habitat may be taller and more moist, but always has thick plant growth.

Feeding

Black-capped Vireos mostly eat insects, which they find by actively hopping and fluttering about thick vegetation. Spotting prey visually, the vireo plucks larvae and adult insects from plant surfaces. The summer diet concentrates on the larvae of moths, butterflies, and beetles, but includes many flies, spiders, leafhoppers, katydids, and many other arthropods. Some seeds are consumed in summer, and they become more important in winter. One study found aster seeds comprised 55% of bulk stomach contents. Young vireos eat insect larvae.

Reproduction

Shortly after males establish breeding territories in March or April, females arrive. The male attends or leads a female through his territory, as she evaluates it and he fends off rivals with songs, displays, and fights. Males may build nest platforms, which they show off during their tours. The pair bond lasts for at least one brood. Under thick cover, the pair builds a nest in a forked branch, 1.5 to 6.5 feet above the ground. The open nest is formed by building a flexible platform of silks and plant fibers, which is then depressed to form a cup. Grasses, strips of plant stems, and leaves are then added to deepen it.

The female almost always lays four whitish eggs, which the pair incubate for 14-17 days. Hatchlings are naked, blind and helpless. Initially both parents tend the young, but males provide most of the food, up to 80% in the early stages. The young fledge in about 11 days and receive care for another four to eight weeks. After the young fledge, females may start a new nest in the male's territory, depart to find another mate, stay to rear the young, or take part of the brood by herself. Juvenile Black-capped Vireos disperse singly or in groups, wandering throughout the surrounding area.

Migration

Migration routes are largely unknown, but birds are thought to avoid the high elevations of the Sierra Occidental and to follow shrubby habitats over plateaus and through valleys. After breeding, southbound migrants may depart in July, and early arrivals appear on the wintering grounds in late August. Young vireos depart first, followed by females and then mature males. Spring migrants arrive between March and April. This species probably travels at night.

  • 8,000
  • 8,000
  • Threatened
Population Status Trends

At the time the species was listed as Endangered, the known population was 191 breeding pairs, with an estimated total population of between 256 and 525 pairs. In 2007, the U. S. Fish and Wildlife Service (USFWS) issued a Five Year Review for this vireo and reported 5,996 singing males in the United States and an additional 273 in Mexico. Surveys on Fort Hood, Texas, counted 1,846 singing males in 2003 and estimated over 5,000 pairs in 2005. On some managed public lands, the increases represent significantly rising populations. Numbers from private lands and from most of Mexico represent recently discovered populations that probably existed before the species was listed.


In 2005, 75% of the U.S. population occurred in only four areas: Fort Hood Military Reservation and Kerr Wildlife Management Area in Texas, and Fort Sill and Wichita Mountains National Wildlife Refuge in Oklahoma. The remainder were scattered over at least 52 locations.

Conservation Issues

Historically, urban development, agriculture, and fire suppression have caused habitat loss and are the major cause of range reductions. When habitat is lost, breeding areas become fragmented and predation, cowbird parasitism, and habitat degradation can cause the extirpation of Black-capped Vireos. Thriving on rangelands and in suburbs, Brown-headed Cowbirds "trick" vireos into raising young cowbirds. Human settlements also support the vireo's predators: cats, raccoons, and skunks. Livestock and wild deer overgrazing seriously affects vireos, because they require the low vegetation eaten by them.

Prescribed burning, increased deer harvest, and rotational grazing have been instituted on some public lands, including Fort Hood, Kerr Wildlife Management Area, and Balcones Canyonlands National Wildlife Refuge. A diverse coalition of agencies and organizations including Audubon Texas work together on a cowbird trapping initiative aimed at decreasing parasitism rates. Black-capped Vireos at Fort Hood, Texas, are a tremendous success story and highlight the power of collaboration between public and private groups. Audubon Texas and Environmental Defense collaborate to offer the Landowner Conservation Assistance Program that encourages private landowners to help Black-capped Vireos.

In June 2007, the USFWS recommended that the Black-capped Vireo be downlisted from Endangered to Threatened, based on successful habitat protection and rehabilitation, increasing populations, newly discovered populations, and successful cowbird management. While populations have increased, 75% of U.S. vireos are isolated in only four separate population centers, and the rest are found in 52 small islands of habitat. While the new discoveries in Mexico are promising, they represent a small fraction of total population. Why should the USFWS rush to reclassify the Black-capped Vireo, just when the power of the Endangered Species Act is having beneficial effects? Conservationists and wildlife managers must evaluate and respond to this recommendation.

What You Can Do

In early spring, look for the Black-capped Vireo at Devil's River State Natural Area near Del Rio, Texas or the Balcones Canyonlands National Wildlife Refuge north of Austin, Texas. A wildlife festival can help you find this songbird. Try the Texas Hill Country River Region's "Nature Quest," held during the third weekend in April around Concan, Texas.

If you own land in the Black-capped Vireo's range, consider managing it for this and other Endangered species. The Texas Parks and Wildlife Department provides guidance with Management Guidelines.

Audubon's Important Bird Area program is another tool for the conservation of Black-capped Vireos as well as other species. To learn more about the Important Bird Areas program in Texas and to learn how you can help with the IBA program.

Listing of this species under the Endangered Species Act has made it possible to learn critical information about the biology of the Black-capped Vireo. Audubon continues to work to ensure that this vital legislation is being used to protect our publicly owned wildlife resources. Check out Audubon's Issues & Action web pages learn of the latest news about the Endangered Species Act and how you can help. 

Find out about actions you can take including Audubon programs and activities.

More Information

Controlling Cowbirds can have short-term, local benefits for beleaguered species, like the Black-capped Vireo, but the techniques and benefits are controversial. Audubon's Cowbirds and Conservation web page reviews the science and the history of this issue.

Learn more about this species and other birds through these resources

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Natural History References

Grzybowski, J. A. 1995. Black-capped Vireo (Vireo atricapillus). In The Birds of North America, No. 181 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, D.C.

Sibley, David Allen. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.

Wilkins, N., R.A. Powell, A.A.T. Conkey, and A.G. Snelgrove. 2006. Population status and threat analysis for the black-capped vireo. Prepared for the U.S. Fish and Wildlife Service, Region 2. 146 pp. Accessed 17 August 2007.

Conservation Status References

Cimprich, David A. and Richard M. Kostecke. "Distribution of the Black-capped Vireo at Fort Hood, Texas." The Southwestern Naturalist 51:1 (January 2006) 99-102.

Grzybowski, J. A. 1995. Black-capped Vireo (Vireo atricapillus). In The Birds of North America, No. 181 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, D.C.

Wilkins, Neal. Black-capped Vireo (Vireo atricapillus): 5 Year Review, Summary and Evaluation. June 2007. U. S. Fish and Wildlife Service, Arlington Texas. 26 pages. Accessed 16 August 2007.