(Vireo bellii) I shot this photo in the morning on April 22, 2012 at the Hansen Dam near Lake View Terrace, California. I first detected this drab bird by its loud, harsh sounding call. It was quite territorial, making circles around me when I was in its territory. Note that this bird lacks the white eyebrow that is found on the similar warbling vireo.
The Bell’s vireo is a bird primarily of the central and southwestern United States and Mexico. The subspecies found in Southern California is the Least Bell’s Vireo which, having suffered loss of habitat to to urbanization and suburbanization, is federally recognized as an endangered species. I once met a biologist who monitored constructions sites near the habitat of the Least Bell’s Vireo to make sure that protected areas were not damaged. Conservation efforts like that seem to have made some positive difference.