The Trumpeter Swan's Road to Recovery
Trumpeter swans have been making a miraculous recovery across Canada and the United States since restoration efforts began in the 1930s, with more than 46,000 estimated to live across North American today. Biologists at Union Slough National Wildlife Refuge in Iowa are working together with colleagues from Iowa State University and Iowa Department of Natural resources to learn more about their breeding site preferences, migratory movements and overwintering.
Trumpeter swan protection and recovery has a long history in North America, that dates back to the Migratory Bird Treaty Act of 1918. This international treaty between the United States and Canada stemmed from the extreme degradation of trumpeter swans and other migratory bird populations that started in the 1800s. By the early 1900s, trumpeter swans were pushed to the brink of extinction by market hunters for their skin, feathers, meat and eggs.
Quality habitats have always been available at Union Slough National Wildlife Refuge and in the almost eight decades since it was established by Franklin Delano Roosevelt, the refuge has been a welcome stopover for migrating waterfowl. Once a trumpeter swan reintroduction program was initiated, it was just a matter of time before there were successful nesting pairs at the refuge.
In 1994, Iowa Department of Natural Resources began releasing trumpeter swans in the state of Iowa. Today's goal is to have a self-sustaining population, and biologists are working to determine how many nesting pairs are needed for such an endeavor. "We recently resored several acres on waterfowl production areas close to the refuge," said project leader Edward Meendering. "Any time we can restore a semi-permanent wetland in the northern part of the District, there's a high probability of nesting trumpeter swans there."
During early settlement time, Union Slough covered 8,000 acres and was considered useless for farming. Many levees and ditches were built in this area in an attempt to control water levels and improve the area for agriculture. In spite of these habitat changes, the area continued to support an abundance of waterfowl, as well as wetland and upland wildlife species. Today, Union Slough National Wildlife Refuge encompasses 3,334 acres of both marsh and upland habitat, and is being intentionally preserved for wildlife like the trumpeter swan. The refuge currently has the highest concentration of nesting swans in the state: this is good news for the species, and a crucial part of maintaining the habitat's balance.
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