Embattled Gnatcatcher Remains Mystery to Most : Profile: The tiny bird may have an identity problem, but it could teach humans a few things, experts say.

It haunts scruffy thickets of brush dotting the coastal hills and valleys. Fluttering amid the sagebrush and buckwheat, incognito in slate-gray feathers, the California gnatcatcher seems the embodiment of the common bird.

But common it is not.

Much like the spotted owl in the Pacific Northwest or the endangered desert tortoise, the tiny songbird has become the centerpiece of an ongoing Southern California slugfest between big business and environmentalists, developers and slow-growth advocates.

Fists continued to fly last week as the state Fish and Game Commission began weighing the gnatcatcher’s destiny--whether to declare it a candidate for endangered species status or, as biologists fear, allow the bird to skitter toward extinction. After half a day of testimony Thursday, the commission put off a decision until late this month.

As the human hubbub plays out, the gnatcatcher has remained something of a mystery, even to some of its most devout supporters and detractors. The bird has been written and argued about incessantly, converted into a symbol of both our embattled environment and our endangered economy. But few people know much about it.

With a wingspan no bigger than your palm and a shrill, drawn-out call often compared to the plaintive mew of a kitten, the gnatcatcher is a bird that would be hard to dislike.

In fact, this tiny creature could teach us a thing or two. Ornithologists say the bird is industrious and hard-working. When it comes to building a nest, both sexes are champion carpenters.

Gnatcatchers appear to stick to the same bushy neighborhood from year to year instead of periodically pulling up roots for greener pastures. They also typically prove devoted mates and doting parents. And the gnatcatcher is a virtuoso singer, trilling its tunes incessantly through the course of a day.

But despite such virtues, the bird has something of an identity problem.

For starters, the gnatcatcher does not eat gnats. Instead, it feasts on other types of small, sedentary insects plucked from certain bushes and brush. Aphids and small beetles are a gnatcatcher’s haute cuisine.

The tiny winged creature has also had something of a roller-coaster ride just getting recognized by biologists as a separate species, independent of other gnatcatchers scattered throughout the continent.

It was not always that way. In 1881, the California gnatcatcher was spotlighted as its own species, distinct from the more prevalent black-tailed gnatcatcher, which thrives in sections of the Southwest and deep in the heart of Mexico. But in 1926, ornithologists reversed themselves and lumped the coastal bird with its inland cousin.

So it stayed for more than half a century. Finally, in 1988 the California gnatcatcher once again ascended to a spot as a distinct creature.

The final proof was in the bird’s voice.

Jonathan L. Atwood, then a doctoral candidate at UCLA, ventured to California gnatcatcher territory armed with a tape recorder. Atwood turned the volume up and, as gnatcatchers flitted about in the bushes, began playing recordings of bird calls culled from a spate of species.

When the chirps of the black-tailed variety and others blared over the loudspeakers, the local gnatcatchers didn’t stir. Birds, after all, typically are not riled up by the calls of other species, which are not considered a threat to steal their mates, Atwood explained.

But when the distinctive mews of the California gnatcatcher echoed through the outback, the birds he was watching would invariably fly to the tape recorder and began attacking it, suspecting that the machine was somehow one of their own trying to invade sovereign territory.

That evidence, along with plumage that is noticeably distinct from the feathers of the black-tailed variety, is cited by most ornithologists as proof that the California gnatcatcher--or Polioptila californica --is its own bird.

And a vanishing bird at that.

As development and agriculture have swept across Southern California this century, all the new houses and farms gobbled up the gnatcatcher’s prime habitat, a rare mix of soft-wood bushes known as coastal sage scrub.

That arid scrub, which drops its leaves during dry spells, is now recognized as among the most quickly vanishing types of vegetation in the United States. Along with its demise has come the disappearance of the gnatcatcher and a host of other birds, reptiles and mammals that make their home in the coastal sage.

About half the remaining scrub is spread through San Diego County. Environmentalists say much of the prime gnatcatcher habitat in Orange County lies in two sweeping stretches owned by developers--the coastal hills held by the Irvine Co. and canyons northwest of Ortega Highway that rest in the hands of the Santa Margarita Co.

Developers who oppose listing the bird as endangered say they have nothing against the gnatcatcher but believe that steps can be taken to set aside a sufficient amount of habitat without blocking their building plans.

Environmentalists strongly disagree. Most fear that the bird is teetering at the abyss.

It fell to Atwood--now a noted ornithologist at the Manomet Bird Observatory in Plymouth, Mass.--to begin the push for state and federal officials to list the gnatcatcher as endangered.

Today, Atwood and other experts suspect there are only 1,200 to 2,000 pairs are left, all of them residing in a narrow band near the Southern California coast from the Palos Verdes Peninsula to the Mexican border. At the present rate, the bird could be gone in 20 years, they contend.

Few birds are as wedded to a particular type of habitat as the gnatcatcher. Studies have suggested that a gnatcatcher will turn back when it reaches the limits of the natural vegetation, sticking close to its beloved coastal sage scrub.

But not all scrub meets a gnatcatcher’s fancy. The birds have proven choosy about their nesting areas, showing a marked preference for low-lying canyons containing sagebrush. They also tend to frequent areas where the scrub is sparse and low slung.

Just how much territory a pair of gnatcatchers inhabit remains in dispute. Some studies suggest it is as little as 2 acres, but others note that gnatcatchers have been observed traversing mansion-sized parcels upwards of 20 acres, giving it a reach far greater than other such diminutive birds.

Much like a human, gnatcatchers do not take too well to having a bulldozer pull up next to their homes. Even when earthmoving equipment does not roll directly into their habitat, gnatcatchers may flee, at least temporarily, amid the noise and commotion, experts say.

But gnatcatchers are not necessarily shy when it comes to humans. Barbara Massey, a Cal State Long Beach research biologist who has studied Southern California’s endangered birds for two decades, notes that gnatcatchers will often come when called.

“They’ll just come right up and practically land on your nose wanting to know what’s going on,” Massey said. “They’re very curious and very alert.”

The birds breed from late February through July. For about a week, a couple works together to build their nest. Less than the size of a clenched fist, the nest is gently cantilevered between the upper prongs of a sagebrush, generally no more than 3 feet off the ground. Grasses, bark strips and small leaves make up the framework, and soft down and spider webs provide the finishing touches.

The female lays three or four thumbnail-sized eggs, each one pale blue with chestnut-red blotches. Both sexes take turns sitting on the eggs. During periods of high summer temperatures, the adults sometimes stand up over the eggs, their wings spread like miniature beach umbrellas to provide shade.

Incubation takes two weeks, then the chicks are raised over about 16 days, with both parents caring for the nestlings.

Fledgling birds are tended to by the parents for about three weeks, although some experts have spotted families of birds that have stuck together through the course of a year. Eventually, however, the youngsters are kicked out of the nest to forge a life on their own away from their parents’ stomping grounds.

Both sexes defend the nest, but infant mortality is high despite such vigilance. More than a third of the nests are destroyed by predators, including crows and ravens, raccoons, foxes, rats and domestic cats.

The birds also do not do well in cold, rainy weather. Experts have found that their inland cousin, the black-tailed gnatcatcher, sometimes uses its nest as a sort of commune during cold spells, as four or five stuff themselves into a single nest for warmth. But the coastal gnatcatcher has not picked up that trick yet, scientists believe.

Experts are not sure just how long gnatcatchers live. But their life expectancy does not appear to be all that good, even without the influence of man. Three-quarters probably do not reach their first breeding season.

Add the unswerving momentum of modern society to the equation and the result for the gnatcatcher will be a steady slide toward extinction, advocates of the bird say. Unless it is protected.

“All species have a right to be here--and a role,” Massey said. “We’re all part of a major ecosystem. What we’re doing on Earth is potentially destructive not just to other species, but to us.”

California Gnatcatcher (Polioptila californica )

Description: Tiny, active bird with slender beak and long, wren-like tail. Light charcoal gray overall, with dark head. Belly and underside of tail are light gray. Lacks pronounced white outer tail feathers seen in similar species. Also called plumbeous gnatcatcher. Length: 4 1/2 inches.

Habitat: Coastal sage scrub throughout Orange, Los Angeles, San Diego and Riverside counties.

Nest: Usually in fork of small shrub; compact nest built of plant down and bound with spider silk.

Diet: Mostly insects and some seeds.

Call: A shrill, kitten-like mew: chee chee chee. Notes: Spotlighted as a potential endangered species. Studies show that only about 2,000 gnatcatchers remain in Southern California. Bird population has declined with the disappearance of coastal sage scrub, the prime gnatcatcher habitat that has been chewed up this century by development and agriculture. Gnatcatchers are industrious foragers and nest builders. Studies have found that many keep the same mate for several seasons. It sometimes maintains a territory a up to 20 acres, far larger than most birds of similar size. The gnatcatcher nests and lays eggs in the late winter and spring, then forces out fledglings to find their own territory after many weeks of nurturing. Only about one out of four birds survives a year, studies suggest. Predators are numerous and include crows, raccoons and common household cats near populated areas.

Sources: Sea and Sage Audubon Society; “The Birder’s Handbook,” Ehrlich, Dobkin and Wheye, Fireside Books (1988); “Field Guide to the Birds of North America,” National Geographic Society (1987); “Birds of Southern California: Status and Distribution,” Garrett and Dunn, Los Angeles Audubon Society (1981).