Bill Sauer sits in a folding chair at the Seal Beach Naval Weapons Station for four hours every Friday morning, peering at the sky in search of predators on the prowl.
Sauer is a volunteer, but he takes his guard duty seriously. The Huntington Beach retiree, along with a handful of others who shoo away ravens, hawks and other raptors, is playing a part in the effort to save the California least tern from extinction.
Sauer's weapon of choice is a soda can full of rocks; others prefer to bang pots and pans, blow whistles, scream and make a commotion. The vast majority of the time is spent standing vigil over the fragile terns.
"You just sit there in a chair and watch," he said. "It's boring, but it's what we have to do."
Terns were once among the most plentiful seabirds in California, with numbers so great that bird watchers in the early 1900s described them as "blackening the sky," said Jack Fancher, a biologist with the U.S. Fish and Wildlife Service's Carlsbad office.
The graceful white birds winter in Central and South America, but nest on California beach strands. But human encroachment and development cut them off from their longtime nesting spots, leading to a drastic population loss.
In 1970, when the California subspecies was listed as endangered, only about 600 pairs were left in the state, Fancher said. For the past three decades, federal officials have been trying to help the species recover, focusing on breeding at six sites in Los Angeles and Orange counties.
The National Wildlife Refuge at the Naval Weapons Station in Seal Beach hosts a nearly 3-acre nesting site on Nasa Island, where NASA tested rocket engines during the Apollo space program.
The site is covered with sand and is encircled by an electrified fence to keep out feral cats, possums and others that would feast on the baby birds. The birds create nests by digging depressions in the sand, and sometimes lining them with bits of shell.
"They're on a private island surrounded by a low-level electrified fence, which is surrounded by another fence and armed guards," said base spokesman Gregg Smith. "They're probably the best-protected endangered species on the planet."
Still, the clustered nests, which would be more spread out in natural conditions, are easy pickings for ravenous crows, hawks, peregrine falcons and other predators. The terns have some defense systems--coloring that allows the eggs and chicks to blend into the sand and a mobbing action in which the adults collectively dive at a perceived threat.
But the raptors can be crafty, sometimes creating diversions with one or two birds to draw away the adult tern, and then creeping in from behind to snatch the defenseless chicks.
In 1999, all the eggs and chicks and many adults were eaten, said Bruce Monroe, co-chairman of the Friends of the Seal Beach National Wildlife Refuge.
Because of that, the organization enlisted a dawn-to-dusk cadre of volunteers to watch over the tern colony.
Monroe said about 50 volunteers work four-hour shifts. If they see a threat, they blow whistles, bang pots and pans, yell and do whatever else they can to harass the birds into staying away.
It's working. Last year, 140 nests produced about 200 fledglings.
Wildlife monitors have found 151 nests this year. About 140 downy sand-colored chicks have already hatched, and there are still 19 unhatched speckled eggs.
There have been some losses--last weekend, 15 chicks were killed. An entire colony that nests at Bolsa Chica was wiped out by crows in May, Fancher said.
"It's a real uphill battle if you're a baby bird," said John Fitch, president of the El Dorado chapter of the National Audubon Society, which provides many volunteers.
At the Ballona wetlands near Venice, crows have been scared from the site using dead crows, crow feathers and a scarecrow. But starlings have become the latest threat.
Another group of volunteers has set up shop there, led by Seal Beach activist Doug Korthof.
The group is planning extra measures for July 4. In past years, revelers have thrown bottle rockets into the fenced refuge. So this year, volunteers received permission from federal and county officials to put up an extra barrier fence 20 feet outside of the normal fence.
Korthof said the hours spent protecting the defenseless birds is its own reward.
"You see the terns and you fall in love with them," he said. "They're drab little birds on the ground, but in the air they're acrobatic, almost like hummingbirds. They make this little cheeping sound--it really gets to you."
"There are very few of them. If people don't protect them, they won't exist."
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California least terns made 151 nests this year at the Seal Beach National Wildlife Refuge. The endangered birds are being watched over by a cadre of dawn-to-dusk volunteers in an attempt to ensure that they're not decimated by birds of prey.
Number of fledglings that survived, by year:
*Fledglings survival for 2001 is unknown
**Each nest equals two breeding adults
Source: U.S. Fish and Wildlife Service