‘Critical Habitat’ for Bird Proposed : Wildlife: U.S. agency wants the status for 48,000 acres of Southland wetlands considered vital to the endangered least Bell’s vireo.

A federal wildlife agency on Friday proposed stepping up protection against development on more than 48,000 acres along Southern California rivers and streams considered critical to the survival of a small endangered songbird.

To help re-establish the population of the least Bell’s vireo, the U.S. Fish and Wildlife Service proposed “critical habitat” status for 48,020 acres in six counties--Santa Barbara, Ventura, Los Angeles, Riverside, San Bernardino and San Diego.

Although the bird is also found in Orange County, no critical habitat was proposed in that county but could be added, said Larry Salata, a Fish and Wildlife biologist.

Development is not banned in critical habitats, but the designation triggers another layer of review by federal agencies.

The U.S. Endangered Species Act of 1973 forbids federal agencies to allow construction that would destroy or otherwise harm habitat that is critical to endangered species--unless an exception is granted.

However, a Fish and Wildlife spokesman said much of the acreage involved in the agency’s proposal is already considered unsuitable for development because of its proximity to flood plains.

Only about 500 nesting pairs of least Bell’s vireos remain in the United States, and about 90% of them nest in the proposed critical habitat area. Several hundred more pairs breed in northern Baja California, but biologists do not have an accurate count in that country.

Salata, who has studied the birds for 12 years, said the fate of the endangered vireo mirrors the destruction of inland wetlands throughout California since the turn of the century.

“About 90% of those kinds of wetlands have been lost,” he said. “Yet they represent one of the most significant wildlife habitats in the state and nation.”

Before the proposal can become law, at least two public hearings will be scheduled. The Fish and Wildlife Service must make a decision by January, 1993.

Although the Endangered Species Act requires that critical habitat be designated at the time a species makes the endangered species list, the process was held up for six years while the federal agency studied its impact on landowners, Salata said.

In February, the National Audubon Society filed a lawsuit against the Fish and Wildlife Service, claiming that the agency was dragging its feet. Audubon officials were unavailable for comment Friday.

Under the plan, the critical habitat would consist of about 9,260 acres along the Santa Ynez River in Santa Barbara County; about 4,240 acres along the Santa Clara River in Ventura and Los Angeles counties; about 9,135 acres near the Santa Ana River in Riverside and San Bernardino counties; and, in San Diego County, 25,380 acres along the Santa Margarita, San Luis Rey, Sweetwater, San Diego and Tijuana rivers and the Coyote and Jamul-Dulzura creeks.

The Least Bell’s Vireo Description: Four to five inches long, with grayish head, back and tail and whitish throat and breast.

Habitat: Dense thickets, shrubs and trees along streams and rivers.

Range: Although once common in California from Santa Clara County south to Baja California, the bird is now found only in small areas of Santa Barbara, Ventura, Los Angeles, San Bernardino, Riverside, Orange and San Diego counties.

Status: The U.S. Fish and Wildlife Service listed the bird as endangered in 1986. The California Department of Fish and Game listed the least Bell’s vireo as endangered in 1980.

Song: Sings as if through clenched teeth: “Cheedle cheedle chee? cheedle cheedle chew!” Inflection rises in the first half and falls in the second half, as though answering its own question.