August 9 2001

   by Michael Field

Scientists say the American island of Guam is overwhelmed with brown tree snakes that can never be driven off but control might be simple -- take the painkiller Tylenol.

   A scientific conference this week at the island’s Andersen Air Force Base was told there are one million brown tree snakes (boiga irregularis), accidentally introduced from New Guinea by the US military in the wake of World War II.

   They’ve damaged the economy through a curious habit of climbing powerlines causing millions of dollars of power outages, they’ve wiped out local wildlife, and although non-venous they have a frightening habit of attacking infants.

   It has no natural enemies.

   Guam, a 549 square kilometre, equidistant from Japan, the Philippines and New Guinea, is a major military and civil hub which has prompted fears that it may accidentally export the snake.

   A conference titled “Brown Tree Snakes 2001” received a paper from Gordon Rodda, a zoologist with the US Geological Survey, who says 80 milligrams of acetaminophen, the ingredient found in Tylenol will kill the snakes.

   It also kills cats, he said, and should placed only where snakes go.

   "There's approximately a million snakes on the island," said Rodda.

   The technical conference has drawn in al alphabet soup of US agencies: US Fish and Wildlife Department, the US Department of Agriculture's wildlife services, the National Wildlife Research Center, the Department of the Interior, the University of Colorado, the University of Northern Colorado, the University of Guam and Guam's Division of Aquatic and Wildlife Resources.

   Guam’s attraction for the snake was the the abundance of food.

   "That sounds strange with the birds being gone, but in the past there's been a lot of rats and the rats are coming back as an important food source, and more importantly, there's lots and lots of lizards and they feed a lot of snakes."

   He said he came up with his population estimate by scientific sampling of different types of habitats.

   He added that there were 32,753 brown tree snakes captured in the last seven years.

   Rodd said there are also ongoing research projects aimed at making the snake traps, a device with a mice inside, more effective.

   He said they will never be able to rid the island of snakes now.

   As a result of its accidental introduction and population explosion, the snake has been responsible for a loss of biodiversity through predation. It has had devastating effects particularly on avifauna such as the Guam rail and Guam flycatcher, small mammals including the Mariana fruit bat, and reptiles such as geckos and skinks.

   Experts believe the snake thrives because of its size and shape. It has a long slender body that can exceed 2.4 meters. It is able to feed on a wide range of prey.

   It reaches sexual maturity at about three years of age and then lays 12 eggs a year.

   At Anderson Base, on the northern tip of Guam, Jack-Russell terriers are used to detect snakes hidden in outbound cargo. Scientists say there are now some increased populations of some bird species around the base as the dogs chase the snakes off.

Copyright: Michael Field