ANS Task Force
Brown Tree Snake
( Boiga irregularis )

Brown Tree SnakeDESCRIPTION: Brown tree snakes may be any length from 18 inches as juveniles to over 8 feet long as adults. They are generally olive green to brown, although they may be somehwhat yellow or have slight saddle-like splotches off red. They have vertical pupils and a large head relative to their body. This species is mildly venomous. They are a tropical species that lives in trees and shrubs but may also be found in grasslands. Brown tree snakes prey nocturnally on small animals, including mammals, birds, and lizards. They also eat the eggs of birds and lizards.

PATHWAYS/HISTORY: This species is native to Indo-Pacific islands including New Guinea, the Solomon Islands, northern and eastern Australia and eastern Indonesia. They are well estabished in Guam where they probably arrived via cargo ships during World War II. Brown tree snakes have been reportedly sighted (but not established) in Hawaii, Texas, and Oklahoma.

RISKS/IMPACTS: Brown tree snakes can be dispered in cargo on planes and ships. In Guam, this species has devestated native populations of forrest birds and could further jeopardize the dwindling native species in Hawaii if allowed to establish populations on these islands. Tropical areas on the mainland United States, particularly near ports, may also be at risk.

MANAGEMENT: Dogs are used to sniff out snakes in outgoing cargo on Guam and in incoming cargo in Hawaii. Removing debris and other daytime refugia may help prevent brown tree snakes from coming in to specific local areas. Traps have been successful at capturing brown tree snakes, but as with most invasive species, erradication of establish populations is unlikely.

WHAT YOU CAN DO: Report any sightings to Mr. Jim Stanford, the Brown Treesnake Rapid Response Team Coordinator for the United States Geological Survey. The 24-hr hot line is 671-777-HISS (4477).

PROFILE CREDIT: David K. Britton, USFWS - IMAGE CREDIT: North American Brown Tree Snake Control Team


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