VANISHING BREEDS

An injured Great Horned Owl hissed nervously in a grassy clearing between two tall sycamores. Missing a wing, the bird could only blink and shift uncomfortably, seemingly aware that the dappled sunlight glinting off his speckled back made him an easy target.

A black-shouldered kite circled lower for a better look at the interloper in its nesting grounds in the Starr Ranch Audubon Society sanctuary within Caspers Regional Park. Then a small falcon streaked in below the trees, only to be enveloped in a barely visible net. Boots strode forward. Human hands scooped up the bird and delicately untangled it from the fine mesh, while the owl used as a lure watched.

“It’s an American kestrel,” wildlife biologist Peter Bloom said as he prepared to put an ID bracelet on one leg and log its vital statistics in a well-worn, clothbound journal--a chronicle of more than a decade of research on Orange County’s birds of prey.

Grim Message

The message contained therein is a grim one.

Hawks, eagles and other birds of prey native to Orange County are vanishing at an alarming clip, said Bloom, 33, a field expert on California raptors, a class of birds with sharp talons and notched beaks. The bearded biologist from East Tustin does frequent consulting work for the state and works with the California Condor Research Center in Ventura.

Man’s continued bulldozing of raptor rangelands will push about half of the remaining 18 native Orange County species into virtual extinction as breeding birds by the year 2000, the biologist predicted. Trapping, pesticide use, even forest fires, have hastened their decline.

Within 15 years, Bloom said remaining pairs of golden eagles, black-shouldered kites, northern harriers, spotted owls, burrowing owls, long-eared owls and turkey vultures would no longer be able to find adequate foraging grounds or secluded nesting areas necessary to produce offspring.

More adaptable species like the American kestrel--one of several species of falcons--as well as red-tailed and red-shouldered hawks and barn owls are expected to breed in reduced numbers, he said. But other occasional visitors will disappear altogether.

“What remains of pristine Orange County is disappearing every day,” said Bloom, who has roamed local woodlands and canyons studying wildlife since early childhood. “If you don’t push the panic button now, and start managing the environment, when do you push it?”

In the south county alone, an estimated 100,000 new homes, a network of transportation corridors and business and commercial centers are scheduled to replace some of the region’s best raptor habitat by the end of this century.

Bloom agreed that development provides much-needed jobs and ensures continued economic health for the area. But he said landowners, businessmen and government planning officials still have a “moral obligation and social responsibility” to look at the environmental impact of these projects.

A solution, he said, would be to increase county park lands and manage them as much for the protection of native wildlife as for the recreational activities of man.

To some degree, that has occurred already. In recent years, the county has required developers to dedicate land enlarging county parks and to maintain a certain amount of open space within their projects.

But for at least some threatened raptors, Bloom argued that the effect has been to “save their bedrooms, but not their kitchens.”

Ronald W. Schlorff, a wildlife biologist with the state Department of Fish and Game, said Bloom’s predictions appear to be based on solid field observations, and are in line with trends occurring across most of Southern California.

Schlorff doubted that there was “much hope for thriving populations of any raptor species” in Southern California.

“Frankly, I’m surprised there is anything left in Orange County since so much of it is privately owned,” said Schlorff, who is based in Sacramento.

Orange County was once a land of sprawling ranchos, rugged mountains and rolling coastal bluffs, grasslands and riparian canyons studded with oak and sycamore. Spawning salmon ran up local creeks. The California condor, now on the verge of extinction, was once a familiar sight. Colonies of bald eagles and peregrine falcons thrived until the 1950s.

Gone with them are prairie falcons, short-eared owls, Swainson’s hawks and ospreys. Other bird populations have dwindled over the last three decades by one-third, some by a half and others to less than one-tenth their previous numbers, Bloom estimated.

Development, however, has not always been the cause, wildlife experts say.

The effects of pesticides and, to a lesser degree, trapping of peregrines caused that species to suffer a serious decline throughout California by the late 1950s. Egg-collecting, a fad among the wealthy, contributed to the problems of the osprey and bald eagle.

In Orange County, 10 remaining pairs of spotted owls, all concentrated in dense areas of the Cleveland National Forest, will “take it in the shorts because of forest fires,” Bloom said.

Hundreds of burrowing owls have been lost in recent years to destruction of their ground level nests in Mission Viejo and surrounding areas. Their numbers have also declined because an imported tall Mediterranean grass makes it hard to find their rodent prey.

There are now fewer than 75 pairs, found mostly on the Seal Beach Naval Weapons Station and the Bolsa Chica wetlands area along the coast in Huntington Beach.

The same tall grass, the seeds of which are thought to have arrived on hoofs of European cattle, has bristling tips called foxtails. Bloom said foxtails are responsible for blindness--and ultimately death--for about 15% of the local population of red-shouldered hawks. The raptors get foxtails in their eyes by diving into grassy fields after small rodents.

Among other raptors Bloom predicts will not produce offspring in Orange County beyond this century are:

- Golden eagles. About seven pairs of nesting eagles remain in Orange County, four on private lands and three in the national forest. In 1965, there were double or triple that number.

- Black-shouldered kites. There are fewer than 40 pairs of these left in Orange County, mainly in coastal valleys and grasslands. They were thought to be making a comeback in Southern California by feeding in freeway median or shoulder strips. However, new research is beginning to suggest that those birds don’t build nests or breed young.

- Northern harriers. As marsh and wetland areas have disappeared here and throughout California, the numbers of this ground-nesting bird, also known as the marsh hawk, have dropped to less than five pair. Unlike most hawks, the harrier detects its prey by its superior hearing rather than sight. It also will attack a much larger bird, even a man, who strays too close to its young.

- Turkey vultures. Less than 10 pairs remain in Orange County because their foraging land has been lost to development. A carrion-feeder, the large, dark bird has a red, featherless head and a six-foot wing span.

Bloom said the secretive Cooper’s hawk, with fewer than 75 nesting pairs left in Orange County, will become very rare as its woodland habitat disappears over the next 15 years.

By contrast, American kestrels, red-shouldered and red-tailed hawks have adapted to living and hunting in relatively close proximity to man. So, too, have barn owls and great horned owls.

Many of the raptors facing a bleak future here are by no means endangered elsewhere.

Schlorff said some of the hawks and eagles that are threatened in Orange County as breeders are thriving in the Sacramento Valley, the Klamath River Basin in Northern California and elsewhere.

But wildlife experts warn that by the time a pattern of decline has been detected, the situation can be critical.

“If you let them go in one place, you can extinguish a species in little pieces until they are completely gone everywhere,” said marine ornithologist Pat Baird, who is doing postdoctoral research at UC Irvine.

“The population of a species has to get so dangerously low before they are considered endangered that it’s almost irreversible at that point,” said Baird.

Then, all it takes, said Bloom, “is some bozo with a pellet rifle to knock out a few adults and you have no breeding birds and no way to replace them.”

Endangered species laws protect the bird, not the land it lives on, wildlife experts say.

“All eagles are protected by an act of Congress--the Bald Eagle Act, which was later amended,” Bloom said. “That means you can’t go out and shoot one, but if you want to build a thousand houses where they live, you can do it.”

The Arroyo Trabuco is a case in point, he believes.

Single pairs of golden eagles, four to six pairs of nesting black-shouldered kites and single pairs of nesting turkey vultures have made the lush, V-shaped canyon their home for generations. The shy raptors will flee, Bloom predicts, when building begins within several hundred feet.

A 935-acre addition to O’Neill Regional Park was dedicated by the O’Neill family--along with 2,125 acres to Caspers Regional Park in 1982--as a trade-off to win approval to build 16,400 homes surrounding the southern end of the arroyo. The Plano Trabuco development on a flat, high plain southeast of the park is expected to become one of the most densely populated communities in southern Orange County.

When county planners were considering the developer’s proposal in 1981-82, the local chapter of the Audubon Society sought a 1,500-foot buffer from the arroyo’s eastern rim to protect raptor nests and some foraging land.

“We didn’t get anywhere near that,” said Eric Jessen, chief planner for the county’s harbors, beaches and parks. After years of negotiations, he said the O’Neill family’s Rancho Mission Viejo Co. has dedicated a 90-acre buffer strip along the eastern park boundary.

“What we got was a fairly modest setback that at its narrowest is 100 feet and probably 700 feet at the widest,” he said. “But it keeps most of the view shed of the park intact.”

Jessen said that “there was a lot of bitterness from the ornithologists and the Audubon people about our inability to get a wider setback.” But he said environmental concerns have to be balanced with the competing interests of a landowner who wants to develop his property.

An extension of the buffer to the nearest ridge line may protect the kite, Bloom said. But golden eagles and turkey vultures need larger rangelands to feed themselves and their young.

“Those individuals are effectively dead--they might as well have been shot,” Bloom said. “In all probability, the birds will wind up being floaters for years in search of a new home.”

Pointing to an eagle’s nest on a ledge above the arroyo that has been used repeatedly for generations, the biologist said glumly that it could be too late already, since none had been seen nesting this spring.

He set up a battered spotter scope, then tried to contain his obvious thrill at the sight of one golden head poking up over the nest.

Soon, its foraging mate appeared, black against the bright morning sun. It alighted on the sandstone ledge and exchanged places on the nest. The other bird stretched its six-foot span of wings and soared upward in leisurely loops, ignoring the harassment of two crows angry at having to compete for feeding ground with the imperious predator.

It seemed a new clutch of eaglets was on the way. Last week, however, Bloom reported that the adult eagles had abandoned the nest for unknown reasons.

“County parks stand to be the most important hope for the future of these birds in Orange County,” Bloom said. “That’s where we are going to make or break it.”