Rare Bird Hatches a Comeback
It had been 74 years since a Xantus’ murrelet nest was found in the lava rock crevices, perched high near the plateau surface of Anacapa Island.
But on May 7, a field biologist studying the rare seabird stumbled upon one. Just 10 days later, at least one fluffy chick from the nest hatched in the wild.
This is big news for the National Park Service, because it’s a sign that the agency’s controversial plan to save the tiny bird from extinction is working.
That plan involved killing off the murrelet’s last unnatural predator on the island: the nonnative black rat, which biologists suspect crashed the island’s fragile ecosystem in a shipwreck decades ago.
Despite protests from animal-rights groups, the park service last fall completed a two-year project to eradicate up to 3,000 black rats from the three islets that make up Anacapa by dropping poison-laced food pellets.
Six months later, the rats are gone, and the island environment in which the rodents wreaked havoc is making a comeback, say officials at Channel Islands National Park.
Researchers have found 17 Xantus’ murrelet nests on the island and in sea caves -- the highest number ever recorded.
In addition, native deer mice on East Anacapa are at greater numbers than normal for the spring, about 8,000.
And side-blotched lizards and Channel Islands salamanders are also thriving there, as survival rates among juveniles have doubled with the rats gone.
“The black rat was the last nonnative animal on this island,” said Kate Faulkner, chief of resource management for the park, as she hiked up the rugged path toward Inspiration Point on a recent media tour of the island.
Nonnative rats are responsible for up to 60% of bird and reptile extinctions in the world, Faulkner said. Anacapa is the 76th island in the world to eradicate rats, and the first off the coast of North America.
“It’s a huge step forward for conservation on Anacapa and in the United States,” she said.
But critics say such a step forward comes at the expense of other animals, including 94 birds -- most of which were juvenile white-crowned sparrows -- found dead on the island after the poisoning. Thousands of Anacapa deer mice also died.
“If the park service really wanted people to have a look at this program, they would have invited the media out directly after the poisoning to see dying animals everywhere,” said Michael Markarian, president of the New York-based Fund for Animals, which sued the park service in 2001 in an attempt to halt the project.
“Seeing it six months later doesn’t give you the full picture of what’s happened,” he said. “It’s like seeing a battlefield after the bodies have all been cleaned up and the blood washed away.”
Park service officials, however, maintain that killing the rats was important for the long-term conservation of the island.
Biologists also say they took pains to offset the possible damage by staggering the poison drop over two years, trapping and removing many birds of prey and capturing more than 1,000 deer mice and then reintroducing them after the eradication program.
“There was a short-term impact, but over the long term there will be a net benefit,” said Gregg Howald, a biologist with the Island Conservation and Ecology Group, a partner in the project.
As the native species recover on Anacapa, Howald said, biologists are making sure the rats are gone by putting out thousands of traps in prime rat habitat over a sustained period.
So far, he said, “There is no sign of rats.”
The project is part of an ongoing effort to restore all five of the islands that make up Channel Islands National Park to their natural state. Since the 1970s, the park service has worked to remove interloping sheep, cats, burros, rabbits, pigs and golden eagles from the islands.
On Anacapa, the eradication effort came with a $1.6-million price tag, not including additional costs for rat prevention and future monitoring, officials said. It was carried out by a partnership that also included the U.S. Fish and Wildlife Service, California Department of Fish and Game and the National Oceanic and Atmospheric Administration.
Funding comes from a court settlement stemming from the 1990 American Trader oil spill off the coast of Huntington Beach, a disaster that resulted in the deaths of thousands of seabirds.
Among the species killed in the spill was the Xantus’ murrelet, a nocturnal seabird that nests on only 12 islands -- including Anacapa -- along the West Coast of North America. State officials have listed the murrelet as a threatened species.
Darrell Whitworth, a wildlife biologist at the Davis-based California Institute of Environmental Studies, has spent the last few weeks working at night to track and monitor the secretive bird.
Nest numbers are up 50% from the previous highest number over three years, Whitworth said.
Even more telling, he said, is the fact that biologists haven’t found a single rat-eaten murrelet egg. Before the eradication, about 60% of the murrelet nests that were found had been destroyed by the black rat’s pin-sharp teeth.
And last week, Whitworth said, researchers came across the first documented nest on Anacapa of a Cassin’s auklet, another very rare seabird, similar to the murrelet.
It was found on West Anacapa -- on Rat Rock, which is now rat-free.
“Birds you would expect to see here are actually here,” Whitworth said. “That’s a good sign for the island.”