The U.S. Army Corps of Engineers, Tulsa District is responsible for monitoring the Interior Least Tern populations on the Arkansas, Canadian and Red Rivers within the District’s boundaries.The District conducts these surveys to ensure compliance with the Biological Opinion they have with US Fish and Wildlife Service pertaining to their reservoir operations and the effect it may have on this endangered species.This endangered bird nests in colony’s on gravel bars and sand bars along the rivers for greater protection of their eggs and chicks.Tulsa District biologists conduct surveys every two weeks on the rivers during the birds’ breeding season, which typically starts in late April.“We count three things on our surveys, the number of adults, the number of fledglings and the number of nests,” said Tulsa District Biologist Jason Person, Interior Least Tern Program Manager. “Adults are typically larger with a black forehead and a white triangle; fledglings will typically be brown or tan with a black stripe.”The birds typically lay two to three eggs and can re-nest, should they experience a disruption with the first nesting.Incubation of the eggs lasts for about 20 to 22 days, with both parents incubating the eggs.Newly hatched chicks become fledglings after three weeks.The Tulsa District works closely with U.S. Fish and Wildlife Service, Oklahoma Department of Wildlife Conservation and Southwestern Power Administration on the Interior Least Tern program.“We work with the Corps on moderating flows within the Arkansas, Canadian and Red River systems to minimize flooding of nests,” said U.S. Fish and Wildlife Biologist Kevin Stubbs. “We’ve also been working on building new habitat and doing surveys to see how the birds are doing. It’s been an ongoing effort and we plan to continue doing those things.”The Tulsa District has used dredge disposal material to create several island habitats in the McClellan Kerr Arkansas River Navigation channel.Utilizing great partnerships with everyone asserting a diligent effort, the Interior Least Tern was proposed for delisting from the Endangered Species List in October 2019.“Bottom line is due to our efforts and the great cooperation we have with other agencies like U.S. Fish and Wildlife, Southwestern Power Administration and Oklahoma Department of Wildlife Conservation, the birds are making a comeback and on their way to being de-listed,” said Person.