Despite major effort, endangered seabird’s numbers drop at L.A. port site

It cost the Port of Los Angeles roughly $350,000 to make a windswept spit of sand on the southeastern edge of the world’s largest container terminal as welcoming as possible for a breeding colony of endangered California least terns.

Among the special touches installed in January at Pier 400 were chick fences; tons of carefully groomed imported sand; and predator controls, including live traps to keep out raccoons, feral cats and crows.

Things didn’t work out as planned. On a recent weekday, port biologist Kathleen Keane surveyed the 15-acre site through binoculars and shook her head in disappointment. “We have five least tern nests so far this year, the lowest number ever recorded here,” she said. “The situation shows that it’s not always ‘build it and they will come.’ ”

It was the sixth consecutive year of declines in nests at Pier 400, following seven years of increases that ended in 2005, when there were about 1,332 nests. Keane attributed the lower numbers to a dearth of small prey fish such as anchovies in near-shore waters. The cause of the decline in prey fish, however, remains unknown.

It’s been a tough year for least terns at several of their 45 federally protected nesting sites from San Francisco to San Diego, despite intense monitoring by a small army of conservation biologists, government officials and volunteers.

The reasons for the declines vary. At a site on Venice Beach, a scarcity of prey fish has caused adult birds to spend more time foraging for food, which has left eggs vulnerable to hungry crows. In San Diego County, the gull-billed tern, an even rarer species of seabird but not listed as endangered or threatened, has fed on least tern chicks. Elsewhere, tern chicks have been eaten by peregrine falcons, which are protected by federal laws that make it a misdemeanor to disturb them.

The problems have renewed the debate over the effectiveness of management strategies that favor protection of the few species that have met the state and federal tests to earn a designation as endangered.

“It’s never easy making wildlife management decisions when they negatively affect another species, and it is all the more complex when one species you are concerned about is eating another species you are concerned about,” said U.S. Fish and Wildlife Service biologist Gjon Hazard.

The population of California least terns, which historically nested on beaches in colonies of varying sizes and densities, declined to about 600 pairs in the 1970s because of loss of undisturbed nesting habitat. The bird was listed as an endangered species four decades ago. Today, the estimated 7,000 pairs and their nest sites are restricted to a few designated locations, some of which are artificial and most of which persist only because of constant management.

“Forcing these seabirds into a few super-dense colonies only magnifies problems associated with food shortages,” said Kathy C. Molina, an ornithologist at the Natural History Museum of Los Angeles County. “It also attracts predators, as well as other seabirds that don’t know those places are exclusively reserved for least terns.… Right now, the situation is fraught with favoritism and emotion when what we really need is hard data,” she said.

In June 2006, more than 400 newly hatched Caspian and elegant terns died after they stampeded off the sides of two privately owned barges in the Los Angeles-Long Beach harbor complex. One of the longest investigations ever conducted by the California Department of Fish and Game culminated in misdemeanor animal cruelty charges filed against three men connected with the incident. Investigators believe the men were attempting to move the barges when the fledglings plummeted into the ocean.

The deaths brought an end to significant tern colonies on the barges, which had been established because there were no available sandy beaches for them to nest on.

The only tern colony site in the Los Angeles-Long Beach harbor that has received protective management is Pier 400, where shotgun shells filled with rice are used to ward off crows.

As in previous years, small colonies of black skimmers and Caspian terns have been allowed to share the grounds, provided they do not make it hard for the least terns to earn a living.

louis.sahagun@latimes.com