- 4.3–4.7 in
- 7.1 in
- 0.2–0.4 oz
- Viréo de Bell (French)
- Vireo Aceitunado, Vireo Oliva, Vireo de Bell (Spanish)
- The Bell's Vireo is the most yellow in the easternmost part of its range, and it gets progressively grayer to the west. The "Least" Bell's Vireo of California and northern Baja California is the grayest, with little yellow or green in its plumage.
- A pair of Bell's Vireos may forage together at times during the breeding season, progressing upward in a spiral, gleaning insects from the vegetation.
- The Bell's Vireo has not been observed drinking water. It may be able to obtain all that it needs from its food.
Dense, low, shrubby vegetation, generally early successional stages in riparian areas, brushy fields, young second-growth forest or woodland, scrub oak, coastal chaparral, and mesquite brushlands, often near water in arid regions.
Insects and spiders.
- Clutch Size
- 3–5 eggs
- Egg Description
- White with sparse spotting.
- Condition at Hatching
- Helpless and naked.
Open bag-like or basket-like cup of grass, straw-like stems, plant fibers, small skeletonized leaves, paper, and strips of bark fastened with spider silk; lined almost invariably with fine, brown or yellow grass stems. Outside decorated with spider egg cases. Suspended from forks of low branches of small trees or shrubs.
Gleans from leaves, twigs, and branches. Sometimes hovers while feeding.
"Least" Bell's Vireo of California considered endangered, primarily from loss of riparian habitat and cowbird parasitism. Populations declining throughout range.
- Brown, B. T. 1993. Bellâ€™s Vireo (Vireo bellii). In The Birds of North America, No. 35 (A. Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The American Ornithologistsâ€™ Union.