PRBO Conservation Science
Quarterly Journal of PRBO Conservation Science, Number 141, Summer 2005: Notes and Discoveries from the Field


Least Bell's Vireo (Vireo bellii pusillus)

Executive Director's Column
Return of the Least Bell's Vireo
Mystery Oil Spill
Bird Bio
Eastern Sierra
Seabirds at Vandenberg
Farallon Auklet News Flash

Characteristics: Grayish-green songbird about 4.5" in length with whitish belly, faint white eye ring, and two pale wing bars. Male and female plumages similar.

Distribution & Status: Current breeding range Southern California to northern Baja California. Winters in southern Baja California. Listed as federally endangered in 1986.

Habitat: Breeds in riparian (streamside) habitat with a layer of dense, shrubby plants under taller trees.

Feeding: Captures insects and spiders by foliage-gleaning from just above ground level to tree top. Larger prey items are held with its foot and smashed with its bill before eating.

Song: Composed of two main phrases, the first ascends and second descends.

Life Span: 3-4 years; an 8-year-old banded male is on record at San Diego River.

Behavior Notes: Males help in all phases of the nest cycle, from building the basket-like nest to incubating eggs and tending chicks. Nests commonly parasitized by Brown-headed Cowbirds.

--Sue Abbott, PRBO Education & Outreach

--Reviewed by Barbara Kus, USGS Western Ecological Research Center, San Diego

Reference: Brown B.T. 1993. Bell's Vireo. In "Birds of North America" No.35

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