Both Sides Like Gnatcatcher Study Results : Land use: Most parkland is not prime habitat, but potential areas exist. Builders, environmentalists say findings support them.

A new study commissioned by county officials concluded that most of Orange County’s protected parkland is not prime habitat for California gnatcatchers, but that some areas have potential for being turned into nesting grounds.

The findings are expected to be important new evidence at a hearing Thursday in which the California Fish and Game Commission will consider naming the songbird a candidate for the endangered species list. Both supporters and opponents of protection for the bird said Monday that they plan to use the county’s findings to support their arguments at the hearing.

The full report was not available Monday from the county Environmental Management Agency, which funded the study performed by environmental consultants. But a two-paragraph summary of the findings says that most of the thousands of acres of coastal sage scrub protected in 14 county parks is too steep for the birds, contains unsuitable types of plants or is in patches that are too small.

“Limited areas that meet the criteria of good quality gnatcatcher habitat . . . exist within all but one of the study sites. However, these areas, for the most part, represent small portions of the total coastal sage scrub and of the total area within each park,” the study says.

The report continued that “many other areas of moderate and low potential habitat also exist.”

The Building Industry Assn. of Southern California has contended that the bird is not in danger of extinction because there are large amounts of habitat permanently protected in public parks and other open-space areas. Environmentalists, however, contend that the bird’s population is declining, and that further development could be a final, fatal blow to the species since up to 90% of its habitat has already been destroyed.

Hugh Hewitt, an attorney for the builders’ group, called the report “great news.”

“It confirms what we have argued all along . . . that there is occupied gnatcatcher habitat under permanent protection,” he said. “It absolutely shows the gnatcatcher can live anywhere in these permanent open-space areas. Low-density habitat can very easily be turned into high-density habitat.”

But Dan Silver, an attorney for a coalition of environmentalists supporting the gnatcatcher listing, said the report is good news to them because “it shows those lands are not a gold mine for gnatcatchers.”

“It certainly doesn’t support the contention of the developers that there is a large amount of excellent habitat out there already protected. The report says something quite different--that the habitat is very limited,” he said.

Several biological reports estimate that up to 90% of Southern California’s gnatcatcher habitat has been destroyed, although a study commissioned by builders estimates that 66% is gone.

Biologists agree that gnatcatchers are choosy about their nesting areas and will not nest in all coastal sage scrub. They prefer low-lying canyons containing sagebrush, at an elevation under 250 meters.

The new study found that the largest amounts of high-quality habitat for the birds occur in Laguna Laurel, a large parcel of canyon land that was recently purchased from the Irvine Co. for preservation as a park, and Wagon Wheel Regional Park east of Mission Viejo.

The report also concluded that there is “potential for enhancement of habitat to support increased numbers of birds” in Aliso/Wood Canyons Regional Park, Salt Creek Regional Park and Irvine Regional Park.

The county plans to do more detailed studies of the parks, including precise counts of gnatcatchers during their nesting season next year.

Southern California developers and builders are vehemently opposing listing the bird as a candidate for the endangered species list because it would mean that its habitat is granted immediate protection for one year while a full review is conducted by Fish and Game biologists.

Orange County and San Diego County developers say that they plan to build upon 3,500 acres of gnatcatcher habitat in the next 18 months. Included are lands earmarked for the San Joaquin toll road, two large Irvine Co. residential projects and the Las Flores community being built by the Santa Margarita Co.