Control and Landscape-Scale Suppression of the Invasive Brown Treesnake

Science Center Objects

The Brown Treesnake is a highly destructive reptile species that has extirpated many native species of birds, bats, and lizards from the U.S. Territory of Guam. For more than two decades branch scientists with the Invasive Reptile Project have developed, validated, and tested the feasibility of Brown Treesnake control and suppression at various spatial scales.

Scientists with the USGS Brown Treesnake Project conduct research on this snake species, including control tool development and testing, ecological impacts, and early detection methods. USGS holds Brown Treesnake Rapid Response Team training courses on Guam throughout the year to develop the skills needed to effectively respond to snake sightings in island environments.

An important aspect of our research is increasing the efficacy of control tools (rodent-baited traps, toxicants delivered aerially and by bait tubes, and visual searches). Our recent island-wide visual surveys along road edges have revealed a high proportion of juvenile snakes across Guam; this is an important finding because juveniles consistently evade our control tools. To further understand juvenile distribution, we are attempting to learn habitat associations for these juveniles by conducting visual surveys on forest edges and interiors. Increased understanding of juveniles is crucial because a large proportion of Brown Treesnakes escaping Guam on cargo, ships, and airplanes are juveniles.

Landscape-scale suppression techniques have improved because of new control technologies developed by U.S. Department of Agriculture (USDA) and partner agencies, chiefly aerial delivery of toxicant-loaded bait. Our scientists are contributing to the development of these methods through control tool validation (for example, confirming that the tool is functioning to eradicate all vulnerable individuals) and by modeling the optimal timing of successive toxicant drop applications.

Our cooperators include U.S. Department of the Interior Office of Insular Affairs, U.S. Fish and Wildlife Service (USFWS), U.S. Navy, U.S. Air Force, Guam Division of Aquatic and Wildlife Resources, USDA Wildlife Services, Hawaii Department of Agriculture, Hawaii Department of Forestry and Wildlife, and Commonwealth of the Northern Mariana Islands Department of Fish and Wildlife.