DVIDS – News – Protection and Preservation of Natural Resources Continue with the Eradication of Invasive Brown Tree Snakes

DVIDS – News – Protection and Preservation of Natural Resources Continue with the Eradication of Invasive Brown Tree Snakes

ASAN, Guam (May 4, 2023) – The Joint Region Marianas (JRM) brown tree snake (BTS) eradication program continues to control the invasive snake species on the island of Guam.

The BTS has disturbed Guam’s ecological balance since the 1950s, when the species first arrived stowed in ship materials. On the island, the tree snakes hunt various small animals including lizards, birds and bats.

“They are opportunistic feeders,” said Megan Parker, natural resources specialist at JRM. “Since their introduction, there has been a cascading effect. They eat the birds; fewer birds means more pests and diseases and then there are no native birds to spread native seeds – that’s another big impact.”

In addition to birds, the snakes also hunt other small animals, including lizards and bats. The ripple effects were significant.

Marc Hall, director of the JRM conservation program, stated, “Brown tree snakes are probably the single greatest limiting factor in the recovery of the listed vertebrates.” [on Guam] – Bats and birds. There are many factors contributing to the recovery of these species, but brown tree snakes appear to be causing most of the problem.”

JRM has been involved in the fight against invasive species for years. Partnerships between the Department of Defense and Department of Agriculture of Guam, US Fish and Wildlife Services and the US Department of Agriculture (USDA) enable prohibition and mitigation.

Banning programs since 1994 have included traps on airport fences and inspections by specially trained sniffer dogs for brown tree snakes. The long-standing programs ensure snakes don’t stow away on military equipment or shipping containers leaving the island.

“It’s a very successful program,” Hall said. “The basic model is still productive. The last live snake to escape Guam was in an ammunition container that landed in Oklahoma in 2006.”

Containment efforts have also been successful. In 2011, 135 hectares of jungle at Andersen Air Force Base were designated as a Habitat Management Unit (HMU) for ecological studies.

Leanne Obra, the JRM Brown Tree Snake program manager, explained that the HMU began as a “multispecies barrier enclosure,” or fenced area, designed to keep out invasive snakes, hogs and deer. The barrier helps control the area for environmental studies of the snake population. The perimeter fence has been snake proofed by a large protruding hump at the fence line four feet off the ground.

“The snakes can’t climb over it because the bump means they have to put about two-thirds of their body weight upside down and their tails can’t support that,” Obra explained.

The HMU is a repository for scientific studies of forest recovery and a benchmark for the island’s ecological health. Because the snake population within the HMU can be closely monitored for any signs of environmental influences, the area is perfect for routine bait casts in the fight against the invasive snakes.

Bait release is an essential part of brown tree snake control. A multi-day helicopter drop occurs every 90 days and is coordinated with the USDA. Damage control will be carried out using a UH-6 helicopter specially fitted for use with an automatic bait dispenser. The helicopter flies over the HMU several times while the automatic dispenser drops Tylenol bait into the trees. The bait makes an easy snack for the arboreal brown tree snake, but the snakes have proteins in their blood that cannot function after ingesting Tylenol.

Over the past five years, the Brown Tree Snake Program has dropped 46,200 lures at the HMU and the impact is being felt. The environmental experts who manage the area note that the snake species is becoming increasingly difficult to find within the HMU, and signs point to a decline in the population.

“We continue to coordinate with our partners, operations personnel and administrators to not only prevent the spread of the Guam brown tree snake, but also to suppress and control brown tree snake numbers to reduce their impact on the island of Guam and the community restore the island’s ecosystems,” Obra said.

Date of recording: 05.12.2023
Release Date: 05.12.2023 01:29
Story ID: 444591
Location: GU
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