New Studies Show Higher Gnatcatcher Count : Environment: 1,800 to 2,100 pairs found in Orange and San Diego counties are double a previous estimate. Conservationists say the figures shouldn’t influence the U.S.’s endangered-species decision.

New studies show that at least 1,800 to 2,100 pairs of gnatcatchers inhabit Orange and San Diego counties, about twice as many as previously estimated.

The population counts, conducted by biologists working for developers and overseen by a state panel of scientists, intensify the debate over the rarity of the small Southern California songbird, which has been proposed for the nation’s endangered species list.

The U.S. Fish and Wildlife Service faces a deadline today for making its decision, but the agency is scheduled to sign a six-month extension this afternoon. The reason for the delay, federal officials say, is a dispute over how numerous the birds are. They say they are especially concerned that questions have been raised about whether the gnatcatchers found in Southern California are a distinct subspecies from those found in Mexico, which are abundant.

Environmentalists say the new data, collected from January through March but just released, still indicates the gnatcatcher is rare enough to be included on the endangered species list. Wildlife biologists say the best indicators of a species in peril are not population counts, which fluctuate greatly from year to year, but chronic and severe losses of its habitat and erratic or low rates of breeding.

However, Southern California’s building industry, which opposes listing the bird, says the new surveys show the federal government has based its proposal to protect the gnatcatcher on “inadequate and inaccurate information.”

“It is a very strong indication that the information that they had to date does not give an accurate picture and that there are a lot of unknowns,” said Sat Tamaribuchi, the Irvine Co.’s senior director of environmental issues. “This certainly supports that gnatcatchers are less threatened.”

A 1990 report by ornithologist Jonathan Atwood estimated that there were fewer than 300 pairs of gnatcatchers in Orange County and no more than 958 pairs in San Diego County. Studies by Atwood, who has researched the bird for more than 10 years, provide the scientific foundation of the federal government’s proposal to list it.

The new studies, however, found 605 pairs in Orange County during surveys of public and private lands, and from 1,200 to 1,500 pairs in San Diego County. Of the Orange County total, 193 were on Irvine Co. property, 177 were in county parks and 148 were on land owned by the Santa Margarita Co.

No data was collected from Riverside County, San Bernardino County or Palos Verdes, which also contain prime habitat for the bird.

For his 1990 study, Atwood did not have access to the developers’ land. The study released Wednesday marks the first time that counts of gnatcatchers on privately owned land in Southern California have been publicly disclosed.

The consulting biologists who conducted the surveys were hired by the landowners. But their work was guided by a state scientific panel chaired by Dennis Murphy, director of Stanford University’s Center for Conservation Biology.

Murphy said the numbers were not surprising and confirm a widespread belief that gnatcatcher populations doubled this year due to heavy rains this past winter and in the spring of 1991. The rains increased the number of gnats the birds feed on and improved the condition of vegetation where they breed, he said.

Murphy said the increase does not mean the bird is out of danger. He said a species like the gnatcatcher can easily double or drop by half in the course of a year depending on rainfall and other natural conditions.

“I’m heartened to see the numbers have spiked upward. Reproduction seems to be up, population seems to be up. But this is part of a long-term dynamic. Frankly, it should not bear on the listing decision,” Murphy said.

“The U.S. Fish and Wildlife Service has to make its decision not on average years, not on good years, but on bad years. From a rainfall and environmental standpoint, this is a very grand year for (gnatcatcher) habitat.”

Environmentalists charge that the Bush Administration’s delay on a gnatcatcher decision is not prompted by scientific debate but by political motives. They say it is designed to postpone the highly contentious decision until after the presidential election and to allow development to continue.

Atwood said Wednesday that the new figures aren’t dramatically different from his, since he had projected about 2,000 pairs existing in Southern California.

“The total population estimate is a non-issue,” Atwood said, “because it doesn’t really matter if there’s 2,000 or 4,000 or 8,000 pairs, if 80 or 90% of their habitat is destroyed.” Developers, however, estimate that the habitat loss is closer to 50% to 65%, and that large amounts are already protected as parkland.

Gnatcatcher Counts

A total of 605 pairs of gnatcatchers were found in Orange County during spring, 1992, counts by biologists--nearly twice the number estimated in 1990. About 90% of gnatcatcher habitat in the county was surveyed. Here is where they were found:

Location No. of Pairs Irvine Co. property 193 County of Orange (public land) 177 Santa Margarita Co. property 148 Chevron property (Fullerton) 27 Coto de Caza 24 Along Santa Ana River 12 Unocal property (Fullerton) 10 Upper Newport Bay, Other 8 UC Irvine 4 Along MacArthur Boulevard (Newport Beach) 2 Total 605

Source: Report to the state’s Natural Communities Conservation Planning scientific review panel