Following discovery of elevated levels of selenium in the water and aquatic life at Cane Ridge Wildlife Management Area in southwestern Indiana, U.S. Fish and Wildlife Service biologists have begun employing management actions designed to discourage endangered least terns and other migratory birds from nesting on the refuge.
On May 20, 2008, the Service received water data indicating levels of selenium may be harmful to nesting birds. Test results received on May 27 showed selenium levels in fish that, if ingested by birds, may be harmful to egg development. As a result, Service biologists decided to immediately stop the flow of water from Gibson Lake into Cane Ridge and to discourage least terns from using Cane Ridge, draw down the Cane Ridge ponds, and remove potentially contaminated fish.
Service biologists have placed flags to discourage least terns from nesting at Cane Ridge. As the water is drawn down, fish will be removed from the ponds. Once the water is fully drawn down, biologists will disc the soil on the bottom of the ponds to redistribute selenium in the soil, allowing for a return to active nesting next year.
Cane Ridge has proven to be an extremely attractive habitat for least terns and other nesting migratory birds. The Service will continue to work with the many partners who have committed time, money and other resources to creating the area which has been named an Audubon Society Important Bird Area.
According to the Service’s Bill McCoy, who oversees Cane Ridge, “We are confident that we can use an alternate water source for the area to provide habitat for migratory birds next year. We will continue to work with Duke Energy and our many other partners to ensure Cane Ridge continues to be a safe place for both people and wildlife.”
Though the public is still allowed to visit the observation sites at Cane Ridge, the low water levels may be disappointing to bird watchers. Ideally, the displaced birds will locate to the state-built Tern Bar Slough nesting pool a quarter-mile east of Cane Ridge. As a reminder, the public has never been allowed access to or fishing in the Cane Ridge nesting pool.
