Biologists Test Bait to Exterminate Rats

Biologists are scouring a 10-acre plot on Anacapa Island to gauge the initial success of an effort to wipe out the island’s population of nonnative black rats.

The rats are a threat to three species of sea birds that nest in the island’s volcanic landscape because they prey on the birds or their eggs, said Kate Faulkner, chief of natural resources management for Channel Islands National Park.

Conservationists hope that ridding the island of rats will increase populations of the threatened California brown pelican, as well as Xantus’ murrelet and the ashy storm petrel.

On Tuesday, a helicopter dropped thousands of pesticide-laced food pellets in the Sheep Canyon area of Anacapa. Faulkner said 20 rats were tagged as part of the experiment so biologists can determine the effectiveness of the bait.

Officials should know in about two weeks if all the rats--about 8 inches long--were killed, she said. Biologists will use data from the test to help refine the next phase of the three-year program--which would drop the bait over the entire east side of the island--next fall. The third phase will attack the remainder of the island.

Biologists are also monitoring the island’s native deer mice, which they do not want to eradicate, Faulkner said.