Predator of Rare Bird Targeted

Anchored near Anacapa Island off the Ventura County coast, biologist Paige Martin holds a tiny baby bird in her hand.

It’s easy to see what makes this species rare: It is no more than a vulnerable bit of fuzz plucked from its chirping mother’s side in the ocean.

And on another boat, biologist Gus van Vliet holds something even more telling: a speckled Xantus’ murrelet egg, serrated, the edges nibbled and cracked by a black rat’s pin-sharp teeth.

On Anacapa Island, in the grotto where Van Vliet found this egg, the black rats get hungry. And they are merciless.

“It’s an extinction game,” Van Vliet says.

State Department of Fish and Game biologists are poised to kick off a program in the fall to kill the island’s entire rat population, the first effort to get rid of up to 3,000 rats living on the three islets that make up Anacapa.

It is a plan scientists believe could save this palm-sized, little black-and-white bird, the Xantus’ murrelet. And they are using the opportunity to study a species they know very little about.

The birds are the innocents, not built for survival on an island where the nonnative black rats are predators. The murrelets are like millions of other island-nesting birds across the world threatened by these unwanted neighbors.

The black rat often shows up on islands via shipwreck. It eats whatever it can, scurrying up cliffs, stealing eggs out from under flustered parents, and sometimes rolling them down bluffs to save for later.

While rat eradication efforts have sometimes worked on islands around the world, many have failed because rats breed so quickly that a single mating pair could have 5,000 offspring in a year.

In the 1980s, the Channel Islands National Park tried to kill off the rats by setting traps by hand, but found the task impossible because of the rugged slopes and hairpin peaks of the island.

This time the National Park Service has decided to use helicopters, which will drop poison pellets in an attempt to exterminate every rat on the island.

The poisoning will be done in stages, with rats on the east end of the island scheduled for extermination in November, and the rat population on other sections of the island to be decimated by the same time next year.

A trial run last year was successful, parks officials said. There is one drawback: The project is also expected to kill some native deer mice. But biologists expect to set aside a group of the mice that will breed later.

The project will cost about $700,000, money that is part of a $9.1-million settlement with BP America, stemming from the 1990 American Trader oil spill off Huntington Beach.

The plaintiffs included a number of regulatory agencies such as the state Department of Fish and Game, the California Regional Water Quality Control Board and the state Coastal Conservancy.

The project was chosen for funds by a board made up of the National Oceanic and Atmospheric Administration, the state Department of Fish and Game, and the Fish and Wildlife Service.

The murrelet--and other seabirds--was among the likely victims of the Orange County spill, so it made sense to pay for its restoration in other Southern California locations where it breeds, said Carol Gorbics, a biologist with the U.S. Fish and Wildlife Service.

It is part of an ongoing program at the national park to return the park to its native state by removing through lethal and other means such nonnative interlopers as sheep, burros, rabbits, pigs and golden eagles.

Murrelets Live Mostly in Ocean

“We’re getting down to the tough ones like rats,” said Bernie Tershy, director of the Santa Cruz-based Island Conservation and Ecology Group, which will conduct the poisoning. “For years and years, no one thought that it could be done.”

The murrelets number about 10,000 in the world and about 3,000 in California, with only about 100 to 200 pairs on Anacapa. They are particularly vulnerable because during breeding season they nest in the same cliffs and grottoes that house the black rat population.

“They’re living right there with the rats,” Gorbics said. “They don’t have a chance.”

Once baby birds are 2 days old, their parents nudge them down the cliffs, where they join their parents in the water. Biologists still know very little about their habits, but they do know they spend most of their lives at sea.

Adult birds fly only at night, when they aren’t bound to be food for sea gulls. As for what the murrelets eat, the experts once again don’t really know for sure. But they think they might eat anchovy larvae.

In the dark off Anacapa Island, the rare birds can’t really be seen. But they can be heard--flapping across the water like wind-up toys and chirping occasionally around the biologists’ boats.

This is where biologists are studying them: One key goal now is to get a baseline of the current bird population. Then, after five years of returning and counting, they will know if the rat kill worked.

At sea, they monitor the birds with radar, checking green and yellow blips on a computer screen, and counting what they see. They can judge the murrelets partly by the size of the dots--too big and it’s probably a gull. Murrelets are faster than the bigger birds, so speed is another clue.

Ecologist Envisions Population Explosion

For now, they see very few in a night. At the absolute most, it’s only a handful. But Tershy imagines a different world. In Mexico, where he has also worked to save bird populations, he has seen other species of seabirds flying in such force that it’s like a storm overhead.

That is Tershy’s hope for the murrelets. The alternative, biologists say, is the end of the species.

The scientists already are petitioning for endangered or threatened species status for the small birds. If the rat kill works, that may not be necessary.

“There’s so much bang for the buck,” said Van Vliet. “In five years, I think, their populations could double.”