Brown Tree Snake | National Invasive Species Information Center

Brown Tree Snake, The "cat eyes" appearance is a distinguishing characteristic. Photo by Gordon Rodda; DOI, United States Geological Survey

Scientific Name:

Boiga irregularis (Merrem, 1802) (ITIS)

Common Name:

Brown tree snake (BTS)

Native To:

Australia, Indonesia, Papua New Guinea (Colvin et al. 2005)

Date of U.S. Introduction:

First detected in Guam in the 1950s (Colvin et al. 2005)

Means of Introduction:

Likely arrived in Guam accidentally in imported cargo (Colvin et al. 2005)

Impact:

Preys on native lizards and birds (Colvin et al. 2005); causes frequent power outages by climbing on electrical wires (Colvin et al. 2005)

Current U.S. Distribution:

Guam; not currently established in the continental U.S.

Spotlights

Interior Announces $4.1 Million to Fight the Brown Tree Snake on Guam (Oct 14, 2021)

DOI. Office of Insular Affairs.

The U.S. Department of the Interior's Office of Insular Affairs (OIA) has announced $4,095,922 million in Brown Tree Snake Control program fiscal year (FY) 2021 funding as administered through the Technical Assistance Program. An additional amount of $1,791,421 from Coral Reef and Natural Resources FY 2021 funds was also announced earlier this year for the purpose of controlling and mitigating other invasive species in the Insular Areas besides the brown tree snake. "Islands are particularly vulnerable to invasive species that disrupt natural, long-standing biological processes and threaten our unique, island eco-systems," said Deputy Assistant Secretary Keone Nakoa. "Each year, OIA provides significant funds to critical efforts seeking to help restore balance."

The Brown Tree Snake Control program FY 2021 funding was divided among several governments and federal partners to include Guam, the Commonwealth of the Northern Mariana Islands (CNMI), Hawai'i, U.S. Department of Agriculture (USDA), and the Department of the Interior. For more information about OIA funds provided to counter invasive species visit: https://www.doi.gov/oia/coral-reef-and-natural-resources-initiative.

USGS Brown Treesnake Research Continues at Guam National Wildlife Refuge (May 22, 2020)

DOI. United States Geological Survey.

On May 14, Director Reilly signed a Memorandum of Agreement with the Department of the Navy and the U.S. Fish and Wildlife Service. The MOA provides for continuity of operations for the USFWS and the USGS with construction of new office and lab facilities on the Guam National Wildlife Refuge in conjunction with DOD’s construction of a Marine Corps firing range. "The USGS has a long history of collaborating with the Department of Defense in support of U.S. facilities and force readiness in the INDOPACOM Area of Responsibility. One of our signature efforts ongoing today is a collaboration with DOD, the U.S. Fish and Wildlife Service, and the local government in minimizing the impacts of the invasive Brown Treesnakes (BTS) and improving BTS controls on military lands on Guam," said Jim Reilly, director of the USGS.

Invasive Brown Treesnake Present on Cocos Island, Agencies Working to Prevent Further Spread (Nov 5, 2020)

DOI. United States Geological Survey.

For the first time, an invasive brown treesnake population has been found on Cocos Island, an 83.1 acre atoll located 1.5 miles off the southwest coast of Guam. The brown treesnake was a major contributor to the loss of nine of 11 native forest birds and significant population declines of several native lizards, bats and other bird species on Guam. They now pose a threat to the wildlife of Cocos Island. Guam Department of Agriculture Division of Aquatic and Wildlife Resources is working with partners to better understand how many brown treesnakes are on the island and the best way to remove them.

New Study Provides Insights for Detecting the Invasive Brown Treesnake (Jan 23, 2020)

DOI. United States Geological Survey.

Researchers from Dickinson College and the U.S. Geological Survey collaborated on field research to understand the ability of human searchers to detect the invasive brown treesnake (BTS) on the island of Guam. Due to their nocturnal and tree-dwelling habits, these snakes are extremely difficult to detect, especially when they are present at low densities in an area. A new study published in the journal Ecosphere helps explain why and provides valuable information on optimizing search methods and search locations that could be valuable if the BTS was accidentally introduced to a snake-free island.

Report to the Congress: Control of the Brown Tree Snake (BTS) (Aug 2008) (PDF | 60 KB)

DOD. Defense Technical Information Center.

This report provides information on specific aspects of the Department’s BTS control program as required by Section 314 of Public Law 110-181. Submitted by The Office of the Secretary of Defense, Deputy Under Secretary of Defense (Installations and Environment).

Federally Regulated

Injurious Wildlife

DOI. FWS. Fish and Aquatic Conservation.

Includes species listed as injurious wildlife under the Federal Lacey Act (18 USC 42), which makes it illegal to import injurious wildlife into the United States or transport between the listed jurisdictions in the shipment clause (the continental United States, the District of Columbia, Hawaii, the Commonwealth of Puerto Rico, and any possession of the United States) without a permit. An injurious wildlife listing would not prohibit intrastate transport or possession of that species within a State where those activities are not prohibited by the State.

Injurious wildlife are wild mammals, wild birds, amphibians, reptiles, fishes, crustaceans, mollusks and their offspring or eggs that are injurious to the interests of human beings, agriculture, horticulture, forestry, wildlife or wildlife resources of the U.S. Plants and organisms other than those stated above cannot be listed as injurious wildlife.
See also: Injurious Wildlife: A Summary of the Injurious Provisions of the Lacey Act (Dec 2017; PDF | 401 KB)

Images

Google Images - Brown Tree Snake

Google.

Invasive.org - Brown Tree Snake

University of Georgia. Center for Invasive Species and Ecosystem Health.

Videos

YouTube - Brown Tree Snake

Google. YouTube; United States Navy.

YouTube - How These Snakes Caused Power Outages in Guam

Google. YouTube; Smithsonian Channel.

Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Brown Tree Snake.

Council or Task Force

Invasive Species Profiles - Brown Tree Snake

Hawaii Invasive Species Council.

Species of Concern Fact Sheet: Brown Tree Snake

Aquatic Nuisance Species Task Force.

Partnership

Global Invasive Species Database - Boiga irregularis (reptile)

IUCN. Species Survival Commission. Invasive Species Specialist Group.

Invasive Species Compendium - Boiga irregularis

CAB International.

Texas Invasives Database - Boiga irregularis

TexasInvasives.org.

Federal Government

Brown Tree Snake Research at NWRC

USDA. APHIS. National Wildlife Research Center.

Brown Treesnake Rapid Response Team

DOI. USGS. Fort Collins Science Center.

Wildlife Damage - Brown Tree Snake

USDA. APHIS. Wildlife Services.

State and Local Government

Brown Tree Snake Program

Commonwealth of Northern Mariana Islands. Division of Fish and Wildlife.

Brown Tree Snake Program

Hawaii Department of Agriculture.

Academic

Center for Resolving Human-Wildlife Conflicts - Brown Tree Snake

Mississippi State University.

Introduced Species Summary Project - Brown Tree Snake

Columbia University. Center for Environmental Research and Conservation.

Citations

Colvin, B.A., M.W. Fall, L.A. Fitzgerald, and L.L. Loope, 2005. Review of Brown Treesnake Problems and Control Programs: Report of Observations and Recommendations (PDF | 262 KB). Published at the request of the U.S. Department of Interior, Office of Insular Affairs for the Brown Treesnake Control Committee.
Integrated Taxonomic Information System. Boiga irregularis. [Accessed Sep 10, 2014].