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The Brown Treesnake on Guam

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How the arrival of one invasive species damaged the ecology, commerce, electrical systems, and human health on Guam: A comprehensive information source.

Drawing of a brown tree snake, courtesy of Dale Crawford

Thomas H. Fritts and Dawn Leasman-Tanner

U.S. Geological Survey
Fort Collins Science Center
2150 Centre Ave., Bldg C
Fort Collins, Colorado 80526 USA

Suggested Citation: Fritts, T.H., and D. Leasman-Tanner. 2001. The Brown Treesnake on Guam: How the arrival of one invasive species damaged the ecology, commerce, electrical systems, and human health on Guam: A comprehensive information source. Available Online: http://www.fort.usgs.gov/resources/education/bts/bts_home.asp


Synopsis

Shortly after World War II, and before 1952, the brown Treesnake was accidentally transported from its native range in the South Pacific to Guam, probably as a stowaway in ship cargo.  As a result of abnormally abundant prey resources on Guam and the absence of natural predators and other population controls, brown Treesnake populations reached unprecedented numbers.  Snakes caused the extirpation of most of the native forest vertebrate species; thousands of power outages affecting private, commercial, and military activities; widespread loss of domestic birds and pets; and considerable emotional trauma to residents and visitors alike when snakes invaded human habitats with the potential for severe envenomation of small children.  Since Guam is a major transportation hub in the Pacific, numerous opportunities exist for the brown Treesnakes on Guam to be introduced accidentally to other Pacific islands as passive stowaways in ship and air traffic from Guam.  Numerous sightings of this species have been reported on other islands, and an incipient population is probably established on Saipan.  It is important that people who may come in contact with the brown Treesnake, particularly on neighboring islands and other high-risk sites, understand the scope of this problem and how to identify the snake so proper action can be taken.

This resource has been developed to provide source materials on the history of the invasion, continuing threats, research results, and containment and management of the brown Treesnake (Boiga irregularis) in Guam and its relevance to other islands and mild continental environments.

 

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