Guam Power Authority is partnering with the U.S. Geological Survey on a Brown Treesnake research project to learn how to protect power infrastructure from snake-caused outages. 

USGS biologists will be conducting night-time visual surveys and monitoring activities adjacent to eight GPA power substations in the northern, central and southern part of the island.

The survey work will begin next month, June 2025, and run through June 2026. 

USGS biologists will be capturing and marking brown treesnakes, from sundown to midnight adjacent to the substations to understand snake activity near critical infrastructure. 

Brown treesnakes are active at night and often found in trees and vegetation so to find these snakes biologists search for them at night with bright headlamps.

Staff working at night will be identifiable in orange Biologist shirts or vests.

Since 2021, USGS has assisted GPA by conducting research aimed at identifying smart solutions for reducing the impacts of invasive brown treesnakes on Guam, especially to reduce the number of outages in and around power substations.

Brown treesnakes cause many unexpected power outages annually. In 2024, brown treesnakes are known to have caused 86 power outages on Guam, with most incidents happening late at night or in the early morning, primarily in southern and central areas. 

GPA lineworkers have captured these snakes on power lines and other infrastructures. 

To combat this, GPA is actively trimming trees, installing barriers and insulation covers at substations, and working with our federal partners on control projects.

In addition to collaborating with USGS on night visual surveys, GPA is also partnering with the U.S. Department of Agriculture Animal and Plant Health Inspection Service - Wildlife Services on a program to remove brown treesnakes from specified GPA operated substations, and along designated transmission lines. 

In FY2024, APHIS-WS captured a total of 869 brown treesnakes by substations through BTS trapping and spot/hand captures.

GPA asks the public to be aware of the USGS team as they conduct their night-time work in and around power substations. 

Survey locations will be marked with flagging material, and we ask the public not to remove these markings along the right of ways. Recently published information about the overall USGS-GPA

Project can be found on this USGS webpage: https://www.usgs.gov/pacific-island-ecosystems-research-center/science/guam-power-lines-and-brown-treesnakes-are

The schedule for upcoming USGS field activities will be available by calling 671-362-8511. 

The schedule and location for night visual survey work may shift slightly due to delays from weather conditions.