Black-capped Vireo

Vireo atricapilla

Order PASSERIFORMES - Family VIREONIDAE

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1. Cool Facts
2. Description
3. Similar Species
4. Sound
5. Range
6. Habitat
7. Food
8. Behavior
9. Reproduction
10. Conservation Status
11. Other Names

The smallest vireo that occurs regularly in the United States, the Black-capped Vireo inhabits low scrublands of Oklahoma, Texas, and northern Mexico. Habitat changes and nest parasitism by Brown-headed Cowbirds have caused Black-capped Vireo populations to vanish across much of the northern part of its historic range and it now is listed as Endangered by the U.S. Fish and Wildlife Service.

Cool Facts

• The Black-capped Vireo is the only vireo that is sexually dimorphic in plumage, where the male and female look different. It also is the only one in which the male takes two years to reach adult plumage.
• Research shows that Black-capped Vireo songs draw from a repertoire of syllables about ten times larger than those of other vireos.

Description

• Size: 11 cm (4 in)
• Wingspan: 18 cm (7 in)
• Weight: 8-10 g (0.28-0.35 ounces)

• Small songbird.
• Black or dark gray head.
• Red eyes surrounded by white spectacles.
• Back olive.
• Underparts white.
• Two pale wingbars.

Sex Differences

Adult male has black cap; female has grayer cap, especially toward the back of the crown and the nape.

Male

Forehead, crown, nape, auriculars, and cheek black. Underparts white, with greenish or yellow flanks. Back olive-green. Wings black with two pale yellowish wingbars.

Female

Similar to male, but slightly duller. Cap gray instead of black.

Immature

Immature similar to adult female, but with dark brown eyes instead of red. Yearling male with gray on nape and back of crown.

Similar Species

• Blue-headed Vireo is much larger, with dark eyes and unbroken white spectacles.

Sound

Song musical and emphatic, usually phrases of two to four notes, interspersed with pauses lasting one to three seconds. Several calls, including a scolding "zhrrree."

»listen to songs of this species

Range

Summer Range

Historic range extended from southern Kansas, through central Oklahoma and central Texas to central Coahuila, Mexico, and Big Bend National Park. At present, Black-capped Vireos breed in only a few isolated areas of Oklahoma, central Texas, and Coahuila.

Winter Range

Winter range not well documented, but includes the Pacific slope of Mexico, and possibly parts of the Mexican interior.

Habitat

Low scrub, often on poor or eroded soils, or in areas at an early stage of succession.

Food

Adult insects, insect larvae, and spiders.

Behavior

Foraging

Gleans from leaves, twigs, and branches. Sometimes hangs upside down or hovers while feeding.

Reproduction

Nest Type

Open hanging cup, made of leaves, grasses, plant fiber, and animal silk, lined with fine grass.

Nest Description

Nest often decorated with spider silk, cocoons, or bits of paper. Cup opening is narrower than nest itself; adult can sit inside nest with only bill and tail tip showing.

Egg Description

Smooth and white.

Clutch Size

Usually 3-4 eggs. Range: 2-5.

Condition at Hatching

Naked and pink, with eyes closed.

Conservation Status

Endangered. Largely extirpated from traditional breeding range in the United States. Cowbird parasitism is a major threat; cowbird removal efforts have evidently led to local increases in Black-capped Vireo populations. Destruction of suitable habitat through urban and suburban development and livestock grazing also have significantly contributed to the species' decline. Habitat maintenance and creation through prescribed burning and other manipulation are a high management priority.

Other Names

Viréo à tête noire (French)
Vireo de gorra negra, Vireo de antifaz (Spanish)

Sources used to construct this page:

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.