A small Bell's vireo subspecies endangered. Restricted to coastal southern California riparian habitats.
§ Quick facts
§ Encyclopedia
Bell's vireo is a songbird that migrates between a breeding range in Western North America and a winter range in Central America. It is dull olive-gray above and whitish below. It has a faint white eye ring and faint wing bars.
Source: Wikipedia — Bell's vireo Licensed under CC BY-SA 4.0
§ Identification
Field marks. Small drab gray-olive vireo with faint white eye ring and indistinct wing bars; paler underparts.
Similar species. Other Bell's Vireo subspecies (interior populations slightly different; ESA-listed only the coastal least Bell's). Hutton's Vireo (rounder head, different range).
Voice. Husky chattering jumble — "cheedle cheedle chee?" rising at end.
§ Diet & behavior
Diet. Insects and spiders gleaned from dense streamside willow thickets.
Behavior. Federally endangered (1986). One of four Bell's Vireo subspecies; this one bred in southern California riparian willow thickets. Populations crashed from 60,000+ pairs (1900) to ~300 pairs by the 1980s due to riparian habitat destruction (water diversions, dams, development) and brown-headed cowbird parasitism. Recovery to ~2,500+ pairs through intensive cowbird trapping and habitat restoration.
§ Range
Southern California riparian
§ Habitat
Riparian willow thickets
§ Threats
Riparian habitat loss, climate change.
§ Conservation status
According to the IUCN Red List, the least bell's vireo is currently classified as Endangered.
§ What helps
Support southern California riparian conservation.
§ Further reading
- Wikipedia — Bell's vireo
- www.fws.gov — authoritative profile of Vireo bellii pusillus
- IUCN Red List · taxon 22705150
- iNaturalist · taxon 13007
- eBird · bevvir
- GBIF occurrence records
- Encyclopedia of Life — Vireo bellii pusillus
§ Sources cited
- USFWS Least Bell's Vireo Recovery
- San Diego Zoo Wildlife Alliance
- California Department of Fish and Wildlife
- IUCN Red List 2018
