Vireos and peppershrikes

(Vireonidae)

Class Aves

Order Passeriformes

Suborder Passeri (Oscines)

Family Vireonidae

Thumbnail description
A group of small, plain-colored songbirds of forests and woodlands; they feed by gleaning invertebrates from plants and may also eat small berries

Size
4–7 in (10–18 cm)

Number of genera, species
4 genera; 43 species

Habitat
A wide range of types of forests, woodlands, and shrublands, from boreal to humid tropical

Conservation status
Critically Endangered: 1 species; Endangered: 1 species; Vulnerable: 1 species; Near Threatened: 2 species

Distribution
Boreal regions of North America, tropics of Central and South America, and temperate woodlands of southern South America

Evolution and systematics

Vireonidae is comprised of 43 species of small arboreal songbirds, divided into four genera. The phylogenetic relationships of the Vireonidae with other families are not totally clear, but they appear to be closely related to the New World warblers (family Parulidae).

Vireonidae is divided into three subfamilies: the Vireoninae, consisting of the true vireos (genus Vireo) and greenlets (Hylophilus); the Cyclarhidinae or peppershrikes (Cyclarhis); and the Vireolaniinae or shrike-vireos (Vireolanius).

Physical characteristics

The vireos are small, plain-colored songbirds; the name vireo is derived from the Latin word for "greenish." The bird has a short, somewhat heavy, pointed beak, with a small hook at the end formed by the overhanging tip of the upper mandible. The wings may be rounded at the end, or may be more pointed. The legs are short but strong. Vireos are typically colored olive gray, olive brown, greenish, or yellowish above; they have a white, light gray, yellow, or yellow-washed breast and belly. Most species have a black line through the eye and a white stripe above it, but some have a light-colored eye-ring. A pale wing bar is generally present. The sexes are colored similarly.

Distribution

Vireos and their allies range widely over the Americas, from the boreal and temperate regions of North America, through the tropics of Central and South America, to the temperate woodlands of southern South America. They occur in northern Canada; throughout most of the United States, Mexico, and Central America; and in most of South America, as far south as Uruguay, northern Argentina, and northern Chile. Northern species of vireos are migratory, while those breeding in the tropics and subtropics are resident.

Habitat

These birds inhabit a wide range of forests and woodlands, including boreal, temperate, and tropical types.

Behavior

Vireos are usually solitary, or they appear as a breeding pair or family group. They sometimes participate in mixed-species foraging flocks during the nonbreeding season. They are deliberate but active birds. Their song is generally loud and melodic, and consists of several repeated phrases. Songs are varied and rather complex, and species may have from about 10 to more than 100 song types. The males sing frequently and persistently, often while foraging; they may even sing while on the nest.

Feeding ecology and diet

Vireos and their allies feed by gleaning insects, spiders, and other invertebrates from foliage, flowers, bark, and other plant surfaces. They also may eat small berries and other fruits.

Reproductive biology

Migratory species pair up soon after their arrival on the breeding grounds in the spring, with the male delimiting and defending the territory by song. The open, cup-shaped nest is made of spider and silkworm webbing, fine grass stems, other plant fibers, lichens, mosses, and feathers. The nest is usually located at the fork of a branch, hanging below the place of attachment, either close to the ground or high in the canopy.

The clutch size is two to five, and the eggs vary in color from whitish to speckled. Both sexes share in incubating the eggs and caring for the young. The incubation period is typically 12–14 days, and the nestlings fledge at nine to 11 days. The fledglings cannot fly well at first but are good at scrambling on branches and in shrubs. They are fed by the parents for about three weeks after leaving the nest.

Migratory species try to nest two to three times each season. Nesting vireos are highly vulnerable to parasitism by species of cowbirds, and to predation by small mammals, snakes, and predatory birds.

Conservation status

The IUCN lists five species in the Vireonidae as being at risk due to loss of habitat as a result of agricultural conversion of forest, logging, and other human activities. The Saint Andrew vireo (Vireo caribaeus) of the Caribbean island of Saint Andrew is listed as Critically Endangered. The Choco vireo (Vireo masteri) is known only from a tiny range in Colombia; it is Endangered because of the loss of most of its montane tropical rainforest habitat. The black-capped vireo (Vireo atricapillus) of Mexico and the southern United States is Vulnerable. The Noronha vireo (Vireo gracilirostris) of Brazil and the Blue Mountain vireo (Vireo osburni) of Jamaica are Near Threatened, but they too have suffered large population declines due to the loss and fragmentation of their habitats.

Significance to humans

Vireos and their allies are not of direct importance to humans. It is important that research be undertaken to better understand the biology and habitat needs of the rare and endangered species of vireonids.

Species accounts

List of Species

Red-eyed vireo

Vireo olivaceus

taxonomy

Vireo olivaceus Linneaus, 1766.

other common names

English: Noronha vireo, yellow-green vireo; French: Viréo aux yeux rouges; German: Rotaugenvireo; Spanish: Vireo de Ojos Rojos.

physical characteristics

6 in (15 cm). Olive green upperparts; white breast and belly. Dark tips on wings, but no wing-bars. Dark red iris; a black line through the eye and a white one above. Head has a gray crown.

distribution

Breeds throughout much of the United States and Canada; winters in Central America and South America as far south as Argentina.

habitat

Deciduous-dominated forest and woodlands.

behavior

A migratory species that defends a breeding territory. The robinlike song is a series of loud, high-pitched, melodious, whistled phrases.

feeding ecology and diet

Eats small invertebrates. Usually forages on foliage, flowers, and limb surfaces, but will also capture flying insects; feeds on small fruits when invertebrates are not abundant.

reproductive biology

Builds a small, cup-shaped nest that hangs from a fork in a tree branch. Lays two to four eggs, incubated by both parents for 11–14 days. Often raises two broods per season.

conservation status

Not threatened, but its numbers are declining in some parts of its range.

significance to humans

Birdwatchers may look for this species.

Bell's vireo

Vireo bellii

taxonomy

Vireo bellii Audubon, 1844.

other common names

French: Viréo de Bell; German: Braunaugenvireo; Spanish: Vireo de Bell.

physical characteristics

4 in (11 cm). A relatively small and dull-colored vireo, with olive-gray upperparts, white underneath, a broken (or incomplete) white eye-ring, and faint whitish wing-bars.

distribution

Breeds in the southwestern and central United States and south to parts of northern Mexico; winters from Baja California to Honduras.

habitat

Shrubby vegetation, such as thickets of willows and mesquite, especially in riparian habitat near streams and rivers.

behavior

A migratory species that defends a breeding territory. The song is a loud, high-pitched, melodious series of simple phrases.

feeding ecology and diet

Feeds actively on invertebrates in foliage, flowers, and limb surfaces. Also eats small berries when invertebrates are not abundant.

reproductive biology

Builds a small, cup-shaped nest that hangs from a fork in a tree branch. Lays three or four eggs, incubated by both parents for about 14 days.

conservation status

Not threatened by IUCN criteria; relatively widespread and abundant. Some populations are threatened by habitat loss due to agriculture, mining, flood-control projects, and reservoir construction. In 1986, the U.S. Fish and Wildlife Service placed a subspecies, the least Bell's vireo (Vireo bellii pusillus), on the U.S. Endangered Species List. The Fish and Wildlife Service regulates human activities in riparian habitat used by the least Bell's vireo in southern California and elsewhere in its range.

significance to humans

None known.

Black-capped vireo

Vireo atricapillus

taxonomy

Vireo atricapillus Woodhouse, 1852.

other common names

French: Viréo à tête noire; German: Schwarzkopfvireo; Spanish: Vireo de Capa Negra.

physical characteristics

About 4.5 in (12 cm); a small vireo with olive-colored upper-parts, white underneath, a yellow wash beneath the wings, yellow wing-bars, and a red iris. Males have a glossy black head and white eye-rings that resemble eyeglasses. Females are similar, but the head is slate gray.

distribution

Breeds in parts of Texas, New Mexico, Oklahoma, Missouri, and north-central Mexico; winters along the west coast of Mexico.

habitat

Open, grassy woodlands with clumps of shrubs and trees. Prefers the low-lying vegetation that grows back after a fire in juniper and oak woodlands.

behavior

A short-distance migrant. Defends a breeding territory. The song is a series of slowly repeated, husky, complex phrases.

feeding ecology and diet

Primarily feeds on invertebrates gleaned from leaves of trees and shrubs, but also eats small fruit.

reproductive biology

Builds a cup-shaped, hanging nest at a branch fork of a shrub or low tree. Lays three or four eggs, which are incubated for 14–19 days.

conservation status

Not threatened by IUCN criteria, though some populations are threatened by habitat loss caused by agriculture, mining, flood-control projects, and reservoir construction. Subject to severe nest parasitism by cowbirds. In 1986, the U.S. Fish and Wildlife Service placed it on the U.S. Endangered Species List in recognition of extensive habitat loss and damage. Efforts are underway in Texas and Oklahoma to trap cowbirds and remove them from nesting areas of the black-capped vireo. The Fish and Wildlife Service regulates human activities in critical riparian habitat used by the black-capped vireo.

significance to humans

None known.

Warbling vireo

Vireo gilvus

taxonomy

Vireo gilva Vieillot, 1808.

other common names

English: Eastern warbling-vireo, brown-capped vireo, Western warbling-vireo; French: Viréo mélodieux; German: Sägervireo, Braunkappenvireo; Spanish: Vireo Chipe.

physical characteristics

About 5.5 in (14 cm). The upper body is uniformly gray, with white underparts, light-yellow flanks, and a white line over the eye.

distribution

Breeds widely in southern and western Canada, through most of the United States, and in part of north-central Mexico; winters in Mexico and Guatemala.

habitat

Hardwood-dominated forests.

behavior

A migratory species that defends a breeding territory. The song is a slow warble.

feeding ecology and diet

Feeds on invertebrates gleaned from leaves, flowers, and branches, and also eats small fruits.

reproductive biology

Builds a small, cup-shaped nest that hangs from a forked tree branch. Lays three or four eggs, incubated by both parents for about 14 days.

conservation status

Not threatened. A widespread and abundant songbird, but its numbers are declining in some parts of its breeding range.

significance to humans

None known, except indirect economic benefits of birding.

Lemon-chested greenlet

Hylophilus thoracicus

taxonomy

Hylophilus thoracicus Temminck, 1822.

other common names

English: Rio de Janeiro greenlet; French: Viréon à plastron; German: Gelbbrustvireo; Spanish: Vireillo de Pecho Limón.

physical characteristics

About 5 in (13 cm). A slim-bodied bird with a short, pointed beak. The upperparts are uniformly olive-green, the chest yellow, the belly and chin light gray, and the iris white.

distribution

Northern South America, southeastern Venezuela and Colombia, eastern Peru, northern Bolivia, and southeastern and Amazonian Brazil.

habitat

Humid tropical forest and forest edges, as high as about 2,000 ft (600 m).

behavior

A nonmigratory species that defends a breeding territory. The song is a series of rapid, rolling "peeer" phrases.

feeding ecology and diet

An extremely active forager for insects and other invertebrates, gleaned from foliage, flowers, and limbs; also eats small fruits. Occurs in mixed-species foraging flocks.

reproductive biology

Builds a cup-shaped nest that hangs from a forked tree branch. Both parents incubate the eggs and care for the young.

conservation status

Not threatened.

significance to humans

None known.

Rufous-browed peppershrike

Cyclarhis gujanensis

taxonomy

Cyclarhis gujanensis Gmelin J.F., 1789.

other common names

French: Sourciroux mélodieux; German: Rostbrauenvireo; Spanish: Alegrín de Cejas Rojizas.

physical characteristics

5.5–6 in (14–15 cm). The body is relatively heavy, the head large, and the beak stout. The back is dark olive-green, the chest and flanks are yellow, the belly white, the top of the head gray, and a broad rufous stripe over the eye.

distribution

Widespread from southeastern Mexico to central Argentina, but missing from most of Amazonia.

habitat

Dry and moist forest borders, scrub, and clearings with trees present, as high as about 6,600 ft (2,000 m).

behavior

A nonmigratory species; defends a breeding territory. The song—a repeated, musical phrase—is given throughout the year. Individual birds have several song types, and there are regional dialects.

feeding ecology and diet

Feeds on insects and other invertebrates gleaned from foliage, flowers, and limbs; also eats small fruits. Occurs in mixed-species foraging flocks.

reproductive biology

Pairs stay together throughout the year. Builds a cup-shaped nest that hangs from a forked tree branch. Both parents incubate the eggs and care for the young.

conservation status

Not threatened.

significance to humans

None known.

Slaty-capped shrike-vireo

Vireolanius leucotis

taxonomy

Vireolanius leucotis Swainson, 1838.

other common names

French: Smaragdan oreillard; German: Scieferkopfvireo; Spanish: Follajero de Capa Oscura.

physical characteristics

About 5.5 in (14 cm). The body is relatively heavy, the head large, and the beak stout. The back is olive green, the chest and belly are yellow, the top of the head and cheeks gray, with a broad yellow stripe over the eye.

distribution

Widespread in northern South America, including parts of Colombia, Ecuador, southern Venezuela, the Guianas, much of Amazonian Brazil, northern Bolivia, and eastern Peru.

habitat

Humid tropical forest, as high as about 6,250 ft (1,800 m).

behavior

A nonmigratory species that defends a breeding territory. The song is a loud, repeated, simple phrase.

feeding ecology and diet

Feeds on insects and other invertebrates gleaned from foliage, flowers, and limbs.

reproductive biology

Builds a cup-shaped nest that hangs from a forked tree branch. Both parents incubate the eggs and care for the young.

conservation status

Not threatened.

significance to humans

None known.

Resources

Books

Bent, A.C. Life Histories of North American Wagtails, Shrikes, Vireos, and Their Allies. New York: Dover Publications, 1965.

BirdLife International. Threatened Birds of the World. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, 2000.

Ridgely, R. S., and G. Tudor. The Birds of South America. Vol. 1. The Oscine Passerines. Austin: University of Texas Press, 1994.

Periodicals

Greenberg, R., D. K. Niven, S. L. Hopp, and C. A. Boone. "Frugivory and Coexistence in a Resident and Migratory Vireo on the Yucatan Peninsula." Condor 95, no. 4 (1993): 990–999.

Hopp, S. L., C. A. Boone, and A. Kirby. "Banding Returns, Arrival Pattern and Site Fidelity of White-Eyed Vireos." Wilson Bulletin 111 (1999): 46–55.

Organizations

BirdLife International. Wellbrook Court, Girton Road, Cambridge, Cambridgeshire CB3 0NA United Kingdom. Phone: +44 1 223 277 318. Fax: +44-1-223-277-200. E-mail: [email protected] Web site: <http://www.birdlife.net>

IUCN–The World Conservation Union. Rue Mauverney 28, Gland, 1196 Switzerland. Phone: +41-22-999-0001. Fax: +41-22-999-0025. E-mail: [email protected] Web site: <http://www.iucn.org>

Other

The Vireo Homepage. 2002. <http://eebweb.arizona.edu/faculty/hopp/vireo.html>

Bill Freedman, PhD

Melissa Knopper, MS