BREEDING BIRDS : WARBLING VIREO (Vireo gilvus)

Description: This vireo has a small, chunky body with gray-green back, white below. The eyeline is dark gray with a predominate white eyebrow. The bill is short and slightly hooked; eyes are brown. It lacks the wing bars and eye rings found in other vireos. Length: 5 inches.

Habitat: Poplars, shade trees, riparian and deciduous woodland.

Diet: Insects, spiders and some berries.

Displays: Courtship displays occur within 30 feet of nest. Male sings courtship song, to which female responds by quivering her wings.

Nest: Deep, cuplike nest suspended from prongs of forked branch. Made of bark strips, leaves and grass.

Eggs: White with brown spots. Length: 0.8 inches.

Call: Soft, slow warbling. Call is wheezy twee .

Notes: Once a common Orange County breeding bird, warbling vireo nesting sites are decreasing in number. Brown-headed cowbird parasitation (cowbirds lay their eggs in warbling vireo nests) and a loss of riparian woodland to development account for warbling vireos moving out of the county.

Breeding bird atlas: To report bird breeding activity in your neighborhood, or to get information on the breeding bird atlas, call Sea and Sage Audubon Society members Sylvia Gallagher, (714) 962-8990, or Nancy Kenyon, (714) 786-3160.

Note: Map is divided into 5-kilometer squares so that Audubon Society volunteers can more easily survey areas on a regular basis.

Sources: Sea and Sage Audubon Society; “The Birder’s Handbook,” Ehrlich, Dobkin and Wheye, Fireside Books (1988); “Field Guide to the Birds of North America,” National Geographic Society (1987); “Birds of Southern California: Status and Distribution,” Garrett and Dunn, Los Angeles Audubon Society (1981).