A subspecies of the Bell's Vireo, the Least Bell's Vireo is on the U.S. Endangered Species List. Habitat loss and nest parasitism by cowbirds are contributors to the birds decline. The Bell's Vireo is named after John G. Bell (1812-1899), a New York taxidermist who accompanied Audubon on a trip up the Missouri River in the 1840s. This bird feeds on caterpillars, aphids, various larvae, and spiders.
Gray upperparts. Gray-white underparts. Faint white eye-ring. Thin white wing bar. Faint dark eyeline and faint white supercilium. Thick bill with hooked upper mandible. Sexes similar. Eastern species has more olive upperparts. 4.25 to 5 inches in length.
Dense willow thickets from southern California into Baja California.
3-5 white eggs with sparse brown markings. The eggs have a 14 day incubation period. Fledging occurs in 11-12 days. The nest is a pendant shaped open cup made from plant fiber and tree bark. The nest is usually built in a dense tree or shrub.
- Mission Trails Regional Park, San Diego
- Bird and Butterfly Garden, Tijuana River Valley