In a controversial effort to rid Anacapa Island of rats, a helicopter dropped bait containing the poison brodifacoum on the eastern end of the island on Wednesday morning.

The Black Rat (Rattus rattus) reportedly preys on the Xantus’ murrelet – a small seabird that builds its nests on the cliffs and sea caves of the island. Opponents of the project contend that the poison could be detrimental to other mammals on the island and that there is no evidence suggesting the rats prey on the seabirds.

The rodenticide project was a collaborative effort between the Channel Islands National Park Service, U.S. Fish and Wildlife Service, California Dept. of Fish and Game, and the National Oceanic and Atmospheric Administration.

The rat extermination is taking place in two different phases, according to Yvonne Menard, the public information officer for Channel Islands National Park. In the first phase, which occurred yesterday, poison was dropped on the eastern end of the island. During the second phase, scheduled for November or December 2002, poison will be dropped on the western end and middle of the island.

Disagreement over the potentially harmful effects of brodifacoum on other mammals, reptiles and birds continues, despite government approval of the project.

Menard said the bait contains half the amount of rodenticide found in rodent-control products sold at grocery stores.

“The bait contains brodifacoum, an anticoagulant, which will cause the rats to die within a few days after eating the bait,” she said. “This application of rodenticide will not accumulate in the environment; it immediately begins to break down into harmless carbon dioxide and water once it lands on the ground, with no harmful byproducts.”

Scarlet Newton, spokesperson for Channel Islands Animal Protection Association, said many animals besides the black rat could be at risk because of the poison.

“The poison causes a slow death over three to ten days by internal bleeding. It effects birds, mammals and reptiles. The poison is not water-soluble. That means marine mammals are also at risk. Dozens and dozens of animals are at risk,” she said.

Newton said she is particularly concerned about the safety of the native Anacapa Deer Mouse, which is not found anywhere else in the world.

“The Anacapa mouse is officially listed as a species of special concern,” she said. “A pretest was run on a small portion of Anacapa Island and we looked at the results of the trial run and every single deer mouse was slaughtered. This project has never been done on an island with a native mammal such as the Anacapa Deer Mouse.”

Menard said some of the Deer Mice would die, but over 150 have been taken from the eastern end of the island and placed in captivity, so they can be released on the middle and western parts of the island later.

Newton said removing the native species from its ecosystem will have a negative impact.

“In captivity – if stress didn’t cause their extinction – they would be selectively breeding and becoming accustomed to captivity, therefore losing their ability to survive in the wild,” she said.

Another controversy surrounding this project is whether the Black Rat is actually a threat to the Xantus’ Murrelet. Newton said there has been no substantial evidence that the bird’s population is declining on Anacapa Island.

“The National Park Service has failed to show evidence [that] the Black Rat harms the Xantus’ Murrelet,” she said. “They found two egg shells broken by mammals. This could be any mammal, maybe even the Deer Mouse.”

Menard said that according to a study conducted by Dr. Harry R. Carter – who has studied Xantus’ Murrelets since 1981 – the Black Rat does prey on the 200 to 400 Xantus’ Murrelet nests on the island.

“Non-native rats are responsible for an estimated 40 to 60 percent of bird and reptile extinctions in the world. Rats prey on birds, reptiles, plants and invertebrates on Anacapa Island,” she said. “[Black Rats] have a large impact on nesting seabirds, particularly Xantus’ Murrelet and Ashy Storm-Petrels.”

The project was funded by the American Trader Trustee Council, which is in charge of the distribution of monies given to the government in 1994 after the American Trader oil tanker settled a lawsuit over an oil spill, Menard said.

“It is not federal money. It’s money from a litigation from that oil spill,” she said.

Newton said the money is being used as it was intended.

“This project would be using 700,000 federal dollars. Monies paid by the oil company to federal government to make up for the oil spill,” she said. “This money was meant to compensate the harm to animals. It seems ironic to use it to cause more death.”