‘We want to have hawks here 200 years from now.’ : Bird’s-Eye View of Progress : Biologist Works to Save Raptors From Path of Development

Balancing 50 feet high in trees as they sway in the spring breezes, Pete Bloom peers expertly into the nests of birds of prey.

He probes the huge masses of twigs and leaves he calls “treasure chests” as he counts and bands the nestling hawks and owls and takes note of the lizards, rodents and other prey they are eating. The parents soar above, shrieking their displeasure.

After last winter’s rains, the birds are thriving. There are more nests and more chicks feasting on an abundance of food.

But there is an urgency to Bloom’s efforts. Despite this spring’s bounty, he says, birds of prey are disappearing from the county at an alarming rate. Much of the best nesting and hunting habitat is in the path of development.

One recent morning he observed that the spreading oak he had just climbed in search of birds may be leveled for the Foothill tollway, a major highway to accommodate traffic generated by South County growth.

The tree now stands in a tranquil canyon that birds share with cattle in Rancho Mission Viejo. It is rooted in the heart of the 937-square-mile raptor study area, stretching from the Santa Ana River in Orange County to the San Luis Rey River in San Diego County, which has been Bloom’s classroom for more than 20 years.

Bloom’s goal is to collect information that government agencies and developers can use to save at least some of the awesome flying predators that now are seen hovering and diving through Orange County’s skies.

Bloom’s study area, which includes six county regional parks and Camp Pendleton, Rancho Mission Viejo, the Irvine Ranch and the Cleveland National Forest, constitutes “one of the richest areas in North America” for nesting birds of prey, he says.

But the 40-year-old biologist laments that since the early 1970s, the numbers of birds have shrunk. He said the population of burrowing owls has probably decreased by 90%, because its preferred habitat of coastal flatlands also is favored by home builders. And he fears for the future of the black-shouldered kite and long-eared owl.

The golden eagle is already pushed to Orange County’s borders, he said, with only one pair left on the edge of the Irvine Ranch in Upper Gypsum Canyon and a few pair in Camp Pendleton and the Cleveland National Forest.

Bloom witnessed the demise of the last golden eagle’s nests in Aliso and Wood Canyons and in the Arroyo Trabuco. Although these South County creek beds were preserved as open space, they were too small to accommodate the eagle, which requires a 10-square-mile hunting territory, he said.

Development encroaching on the woodsy Arroyo Trabuco from the adjacent communities of Mission Viejo and Rancho Santa Margarita also threatens to evict other birds of prey with far-ranging foraging needs, such as red-tail hawks, he said.

Ironically, the Santa Margarita Co., developer of Rancho Santa Margarita, has been Bloom’s chief benefactor for the past five years, providing $250,000 to support his long-term raptor study. The O’Neill family that owns the company and 35,000-acre Rancho Mission Viejo have also allowed Bloom to traverse the raptor-filled ranch.

Bloom acknowledges that it has been tricky for him to walk the “tightrope” of being a biologist under contract to a developer.

Tony Moiso, chief executive of the Santa Margarita Co., said Bloom’s raptor study has helped him satisfy Moiso’s curiosity about the natural resources of the ranch. Years ago Bloom was introduced to the company management by Donna O’Neill, Moiso’s aunt, who is an enthusiastic environmentalist.

Moiso said he and other O’Neill family members already have determined to save from the bulldozers 20,000 acres of ranchland south of Ortega Highway, in addition to land they donated for O’Neill Regional and Ronald W. Caspers Wilderness parks as a condition for other development.

However, Moiso said that because of the sharp decline in land sales to home builders over the last two years, the Santa Margarita Co.’s profits have plummeted, forcing it to lay off even some senior employees. So he said he no longer can justify funding Bloom’s raptor studies at about $50,000 a year. It is likely that the funding will be cut substantially, and Moiso has encouraged Bloom and company personnel to look for alternative sources.

Also, Moiso frankly concedes he is miffed that Bloom recently accepted a position as vice president of the Sea and Sage chapter of the National Audubon Society, the same group that has embroiled the company in a costly court battle over its plans to develop the 1,000-acre community of Las Flores.

Bloom, however, said he would readily resign his Audubon post in exchange for the company’s continued support.

“This project is far more important,” Bloom said. He noted that his long-term study, sponsored by the Western Foundation of Vertebrate Zoology, is one of only two in North America that looks at multiple species of raptors. The other is at the Snake River Bird of Prey Area in Idaho.

Bloom said he believes mistakes that government agencies have made in choosing the right acreage to preserve for birds of prey could be avoided with additional knowledge of what it takes for specific species to survive.

“We are way behind in terms of quantifying for planners what they need to know to preserve habitat,” he said, “and we need to act quickly to preserve the most important habitat, because in 20 years Orange County will be completely developed. We want to have red-tail hawks here 200 years from now.”

Bloom is considered by developers and naturalists to be the ultimate authority on Southern California raptors.

“Whenever anybody has any questions on hawks, they call Pete,” said Lee Jones, director of resources management for Michael Brandman Associates, an environmental planning and consulting firm based in Santa Ana.

Bloom is methodically collecting information about 13 raptor species that nest in his study area: the red-shouldered hawk, red-tailed hawk, common barn owl, great horned owl, Cooper’s hawk, long-eared owl, black-shouldered kite, golden eagle, northern harrier, western screech owl, burrowing owl, turkey vulture and spotted owl.

He seeks to learn the most intimate details of the birds’ lives from their eating and mating habits to the path of their adolescent wanderings in search of a territory, to the effects of fire, weather changes and pesticides on their breeding.

Each spring Bloom heads for the wild, carrying with him a map of nests he has discovered over the years and a string of aluminum foot bands issued by the U.S. Fish and Wildlife Service that he wears as a necklace. “I try to band as many youngsters as I can,” he said.

Of the 300 to 700 birds he and his assistants band each year, he said, about three-fourths are chicks still in the nest. The rest are adults that have to be caught in nets. Hawks and kites are often lured by using an owl, which they consider a threat to their young and will dart at menacingly, flying low into the trap.

The reason for the banding, Bloom said, is to track the movement of the birds. But the number of banded birds that are recovered is relatively small. “For every 100 birds I band, I get two back,” he said.

By this laborious method, Bloom said, he has discovered to his amazement that some red-tail hawks that leave the nest in Orange County fly north as far as Oregon.

But he knows most about the red-shouldered hawk. That species was the subject of a three-year study in which he harnessed tiny radio transmitters to the backs of 26 fledglings. He learned that while most of the birds eventually nested within 20 miles of their birth nests, some flew as far away as Las Vegas and San Luis Obispo.

He also found that red-shouldered hawks usually nest in their second year. “We established that red-shouldered hawks maintain the same territory and mate for life, although there are occasional acts of infidelity,” he said with a chuckle.

Another finding important to preserving the species, he said, is that a pair of red-shouldered hawks require about a square quarter-acre of good forage to survive, about 80% of which must be in riparian or oak woodlands.

Bloom said he hopes that the results of his red-shouldered hawk study, which are being published in the Journal of Wildlife Management, will curb the routine uprooting of trees along river banks for flood control.

He argues that wilderness acreage set aside in trade-offs for development should be juxtaposed to form large expanses of habitat, rather than fragmented into smaller parks that better serve humans than wildlife.

Bloom avows that he will find a way to continue his work. Formerly, he said, he studied raptors without pay while earning his living as a consultant and wallpaper hanger.

“It is what makes me tick,” he said of his raptor study. “There is nothing I would rather be working on.”