Federal officials on Sunday dropped 2,000 mice full of painkillers onto the unincorporated western Pacific U.S. territory of Guam, in order to combat the invasive brown tree snake, which has devastated the bird population in the region.

Shortly after World War II, the mildly venomous Boiga irregularis was accidentally transported from its native range in the South Pacific to Guam, likely as a stowaway on a boat. With its only natural predators being feral pigs and mangrove monitors, brown tree snake populations reached unprecedented numbers in Guam.

Not only have the snakes devastated populations of endemic forest species in the area, they’ve also caused thousands of power outages, have eaten pets, have terrified tourists and have envenomated small children. The aggressive-when-cornered brown tree snake, which can grow up to 9 feet long, packs a mild neurotoxin, though as it is rear-fanged (the fangs are at the back of the mouth), it’s difficult to inject a dangerous dose into an adult human. Though, the snakes are dangerous to small children, who have a lower body mass.

Guam has been using acetaminophen, only 80 grams of it can kill the snakes, in attempts to eradicate the invasive species. According to Dan Vice, a U.S. Department of Agriculture official, “The process is quite simple. The helicopter is going to make low altitude flights over the forest at relatively slow speeds they’re going to be certified pesticide applicators inside the helicopter delivering the baits out of the helicopter on a time sequence.”

The latest mice-drop is the fifth so far this year, near Andersen Air Force Base, where the U.S. Department of the Interior had estimated in 2005 that the snakes caused 80 outages and about $4 million in subsequent repairs.

In related Guam news, two unarmed U.S. Air Force B-52 bombers entered a Chinese air defense zone on November 25, defying China’s expanding claim over an island chain in the East China Sea. The planes took off from Andersen Air Force Base, located roughly 4 miles northeast of Yigo, near Agafo Gumas.

Image via Wikimedia Commons.