Love on a Ledge : Mating Peregrine Falcons Coexist With High-Rise Workers

They’ve been mating since 1988 in relative seclusion on a ledge of the California Federal Building, but this spring a pair of endangered peregrine falcons have company: 40 construction workers who are gutting and remodeling the 27-story skyscraper.

The predatory birds live and hunt year-round off the ledge, nesting in a plastic, gravel-filled tub.

But like humans, the lovers like their privacy. So the Wilshire District building’s owner has rescheduled the often noisy construction to give the birds some peace, forcing work crews to hopscotch down several floors until the mating season ends in early May.

“We tiptoe around them,” construction superintendent Sam Awe said Wednesday, laughing a bit sheepishly.

“They are our first tenant,” quipped Milt Swimmer, a partner with J. H. Snyder Co., the building’s new owner, “and they’ve got a long-term lease.”

As construction workers in masked outfits resembling space suits cleared asbestos from the 14th floor, bird experts Wednesday morning removed three falcon eggs from the nest on the 25th.

The eggs were flown to UC Santa Cruz, where they will be hatched in an incubator and the nestlings eventually released into the wild along the California coastline.

The eggs were replaced with look-alike “dummy” eggs to prevent the mother falcon from being traumatized by the loss. One of the hatchlings will be returned to the nest when it is 2 weeks old.

“Everything went fine. The birds were hardly disturbed,” said Brian Walton, coordinator of the UC Santa Cruz Predatory Bird Research Group.

Like the brown pelican, the peregrine falcon population was devastated by DDT poisoning, he said. Contamination from the chemical left the falcons’ egg shells so fragile they could not withstand the mother’s weight.

In an effort to renew the peregrine population, Walton’s group released several of the birds in 1984 near metropolitan areas with high-rise structures. Fifteen years ago there were but two pairs of peregrines left in California, Walton said. They number about 100 pairs today.

The peregrine is able to survive in the urban landscape, experts say, because high-rise buildings are ideal for the cliff-dwelling birds. The falcons mate for life and roost in one site. They feed strictly on other birds, which the falcons nab during dazzling midair swoops and dives.

The group monitors four peregrine nests in San Diego, Long Beach and Los Angeles.

Presently, there are two peregrine pairs nesting on Los Angeles high-rises--the other on the roof of the 38-story Union Bank building downtown.

Until the construction crews came along last month, said Mike Clark, nest watcher for the UC Santa Cruz group, the California Federal peregrines had found a perfect little home.

The male, released in Westwood in 1983, found the ledge the same year when he was with another female, who died. With a grin, Clark noted that the male’s current mate, a younger female, was looking for new territory and “a single male. And here he was. It worked out perfect.”

The male had to prove he could provide for the female “by hunting a lot and bringing her back . . . a lot of food” in order to win her over, Clark said.

In 1989, Walton said, the female laid her first eggs.

But in March, when the multimillion-dollar remodeling job began at the building near the Los Angeles County Museum of Art, Walton approached the Snyder company and explained the falcons’ delicate mating situation.

“They were very accommodating,” he said.

The falcons’ nest--basically a cat litter box filled with gravel--was moved to a ledge on a floor away from the construction work.

But some of the gravel was left behind, and the birds went back to the previous nesting site. As a result, construction was halted and moved, Swimmer said.

Awe said his work crews respect the birds’ privacy and have grown fond of the pair.

“I bring my sons up here to see them,” the construction superintendent said. “They’re 6 and 1. They love them.”