Mouse bombs target Guam tree snakes

Posted September 20, 2010 15:52:00

Brown tree snakes infest forests on the Pacific island of Guam, but now authorities are taking their battle against the reptiles to the skies.

The US department of agriculture is dropping dead mice injected with poisonous chemicals onto forests to provide deadly snacks for the snakes.

It has also stepped up trapping to prevent the snakes from hitching a ride on boats and aircraft to other Pacific islands.

The snakes have wiped out the island's native population of forest birds since being accidentally introduced to Guam more than 50 years ago.

They also cause millions of dollars in damage and power shortages when they become entangled in electric wires.

The US department of agriculture's assistant state director of wildlife services in the Pacific, Dan Vice, told Radio Australia's Pacific Beat that officials had previously used detector dogs to track the snakes.

"In the last five years we have also received the official go-ahead from the US Environmental Protection Agency (EPA) to use an oral toxicant... as a poison for brown tree snakes and we are working on developing the technology to deliver this toxicant aerially," he said.

This targets more inaccessible blocks of terrain where snake populations are quite large, Mr Vice said.

He said a mouse corpse was attached to a flotation system so it would "float relatively slowly to the ground and actually hang up in the forest canopy".

"What we want to do is keep the bait from hitting the ground, actually keep them in the tree so that the snake, which lives in the trees, will be virtually the only thing that can get to that bait," Mr Vice said.

This protects other species and prevents bait falling into crevices or otherwise missing the snakes, Mr Vice added.

"We're putting radio transmitters in some of the baits. When we drop them, we can go out and find them in the forest and then we can track them and we can determine what actually happens to them," Mr Vice said.

A pilot study of 10 radio-equipped mouse corpses found snakes ate a proportion of the bait and the native wildlife of Guam had become a little safer.

"We're anticipating moving this project forward in the coming years," Mr Vice said.

"So we were out testing our navigation system and testing the bait delivery and all of the things that we need to do to make sure that the system works before we go on a larger scale."

Topics: conservation, environment, human-interest, animals, guam