Poisoned mice airdrop to combat snakes

Declaring war against invasive brown tree snakes infesting the Pacific U.S. territory of Guam, wildlife officials plan this spring to bomb the island with dead baby mice stuffed with a common pain-killing medicine that is poisonous to the reptiles.

Brown tree snakes, believed to have been inadvertently carried to Guam around the end of World War Two aboard U.S. military vessels, have become major pests blamed for wiping out native bird populations on the island.

Wildlife officials have worried for years that the snakes, which have no natural predators on Guam, could one day reach other Pacific islands, especially Hawaii, nearly 4,000 miles (6,400 km) to the east, raising further environmental havoc.

"Guam is a very unique situation," said William Pitt, a wildlife biologist at the U.S. Agriculture Department's National Wildlife Research Center in Hawaii. "There is no other place in the world that has a snake issue like Guam."

The project is set to begin in March or April with dead newborn mice being dropped by helicopter over jungle areas where the snakes are most heavily concentrated.

One initial target will be the vicinity of Andersen Air Force Base, which is surrounded by dense vegetation and is seen as a potential starting point for snakes that might end up as stowaways aboard departing aircraft.

Stuffed into the mouth of each infant mouse will be acetaminophen, the active ingredient in Tylenol and other over-the-counter pain-relief medications, which is toxic to snakes "and not a lot of other animals," Pitt said.

In an attempt to keep the baited mice off the ground, each tiny rodent will be attached to a strand of ribbon between pieces of cardboard designed to drop in a loop and catch in the canopy of trees, he said.

The goal of the aerial assault, which will eventually involving the dropping of some 2,000 mice in all, is not to eradicate but to curtail and control the brown tree snake population on the island, Pitt said.