Columbia Gorge News: Bullfrog removal protects vulnerable species in the Columbia Gorge and Glenwood Valley

By Sienna Krulis, Adam Yawdoszyn, and Jack Fogarty, Mt. Adams Resource Stewards

As night descends over the watersheds of Mount Adams and the Columbia Gorge, many animals retreat into their burrows to rest until dawn, but others rise in the darkness. Hungry and patient, the golden eyes of invasive American bullfrogs breach the surface of quiet waters, ready to lunge indiscriminately at any small sign of movement. Under the same moonlight, a different kind of hunter navigates through the water: a team of trained bullfrog removal technicians, armed with waders and high-powered headlamps. They are working to restore balance to native ecosystems disrupted by this aquatic invader.

Populations of two state-endangered native species — the Oregon spotted frog and Western pond turtle — are threatened by American bullfrogs, which were introduced to western watersheds in the late 1800s and opportunistically prey upon anything they can fit in their jaws. Growing much larger and reproducing at faster rates than any other frog in the region, they are a leading cause of population decline for many local species.

In partnership with the U.S. Fish and Wildlife Service, the Glenwood-based nonprofit Mt. Adams Resource Stewards (MARS) introduced the Bullfrog Removal Action Team (BRAT) program in 2020 to attempt to reverse the steep decline of native Oregon spotted frogs in the Glenwood Valley. Six BRAT technicians, based at Conboy Lake National Wildlife Refuge, systematically remove bullfrogs while they are most active between May and October. Tracking bullfrog calls from over half a mile away, then heading deep into wetlands either on foot or in small boats, the BRAT crew has removed more than 60,000 bullfrogs since 2020. And it’s working: annual spotted frog surveys show a tenfold increase in the native population since it reached its lowest point shortly after bullfrog removal efforts began.