Notes about your surroundings.

Vireo News--A lone male least Bell’s vireo was spotted May 16 in Irvine at the Bonita Canyon Reservoir. The endangered songbird was once a common breeder in Orange County but has been reduced to an isolated sighting every three or four years.

The main culprits in the bird’s diminishing local population have been flood controls and other development, which have decimated the riparian habitat the bird favors, and competition with the brown-headed cowbird. An introduced species, the highly successful cowbird is a nest parasite--it will lay its eggs in the nests of the smaller Bell’s vireo and other birds, which then raise the young as their own.

There is some good news for the vireo, which had been reduced to about 250 pairs in the wild. In the Prado Basin, just over the Riverside County border from Orange County, 40 territorial males were found in mid-May, up from 24 found in 1986. Efforts to trap the cowbird are apparently paying off. The bad news is that the colony is in the path of a planned Santa Ana River flood control project.

Other rare sightings include a male bluewing warbler, spotted in Huntington Central Park on a drizzly Memorial Day morning by birder Doug Willick. The sighting of the vagrant Eastern bird--the first ever recorded in the county--quickly drew a crowd of about 40 avid bird enthusiasts.

And on May 17, near the mouth of Gypsum Canyon, Richard Erickson made the sixth recorded sighting in the county of a yellow-throated vireo, another vagrant species. “It’s probably the prettiest of all the North American vireos,” said Willick, who compiles rare bird sightings in the county for the National Audubon Society. “It’s a real rare bird in this state.”