Sick Birds Washing Ashore Puzzle Avian Experts

Avian experts are trying to determine why an unusually high number of California brown pelicans are washing up on local shores -- weak, dehydrated and near death.

Tissue samples from birds that have died have been sent to laboratories run by the state and federal governments and the UC Davis veterinary school.

The young birds, members of an endangered species, are being treated by bird specialists at Sea World San Diego. More than 100 birds have been brought to the park in the last two weeks.

So far, bird experts are unable to explain the phenomenon.

“I don’t have a clue,” said Jim Peugh, chairman of the conservation committee of the local Audubon chapter.

Sea World veterinarian Judy St. Leger said Monday that necropsies have not yielded a cause. Among other things, laboratory tests will look for signs of West Nile virus, she said.

“They’re acting as if they’re starving,” St. Leger said.

Ten birds have been nursed back to health and released but more are arriving each day, plucked from beaches from La Jolla to Oceanside. The birds are being given vitamin injections, fluids and either a gruel-like formula or whole fish.

The California brown pelican, identifiable by its long pouched bill and ungainly appearance, is a water bird that thrives on rocky shores, cliffs and coastal river deltas. It catches fish by swooping into the water at high speed from 20 to 60 feet.

In recent years California brown pelicans suffering avian botulism have been brought to Sea World from the Salton Sea, the putrid body of water that straddles Riverside and Imperial counties and serves as a migratory stopover on the Pacific Flyway. But the latest birds show no similar signs, St. Leger said.

“These are not Salton Sea birds,” she said.

Historically, a change in the fish population can imperil sea birds. “The abundance of fish can shift very quickly and very dramatically,” said Phil Unitt, curator of birds at the Natural History Museum in San Diego.

A decade ago over-harvesting had reduced the numbers of Pacific mackerel, Pacific sardine and northern anchovy. All three species are key sources of food for the California brown pelican.

But efforts by the state Department of Fish and Game are thought to have increased the fish population off the Southern California coast.

Also, state and federal wildlife agencies protect California brown pelican breeding colonies in the islands that comprise Channel Islands National Park and the Moss Landing Wildlife Area near Monterey.

While some outbreaks of avian sickness or depletion can be anticipated by changes in weather or fishing patterns, there has been no warning that the pelican population was being threatened, officials said, until the sickly juveniles started arriving.

“This is very, very unusual,” St. Leger said.