Researchers with the Minnesota Department of Natural Resources, the University of Minnesota and the Three Rivers Park District are placing radio collars on 35 trumpeter swans this summer, as part of a broader effort to study where the majestic birds migrate in the winter, and what kind of habitat they utilize.
The neck-mounted transmitters record the swans’ GPS location every 15 minutes.
“Results of this study will provide information about migration, year-round movements, mortality risks and swan use of various habitat types,” said David Andersen, a researcher with the Minnesota Cooperative Fish and Wildlife Research Unit at the U of M.
Researchers capture the swans during a period when their feathers are molting and they can't fly. Fully grown swans are huge — they can weigh up to 35 pounds.
"Most swan researchers have scars on their bodies, from claw marks, and being whacked by a wing, so you do have to hold them tight,” said John Moriarty, a senior wildlife manager with the Three Rivers Park District.
But Moriarty said when held tightly, the bright white swan, with a black bill and feet becomes docile, sometimes even wrapping its head around the researcher’s neck.
Trumpeter swans were nearly wiped out from North America by the late 1800s, the victims of overhunting and habitat loss. By the 1930s, only 69 trumpeter swans remained in the lower 48 states, living in remote southwestern Montana.
A few decades later, the Hennepin County Park Reserve District — now Three Rivers Park District — obtained 40 swans from Montana to establish a breeding flock, and swans began to nest in Minnesota again after nearly 80 years.
The Minnesota DNR also collected trumpeter swan eggs from Alaska, incubated them and reared the young, and then began to release them to different parts of the state.
The reintroduction program has been a huge success. When the DNR started the program in the 1980s, its goal was 350 swans. In 2015, a statewide tally counted more than 17,000 swans, in all corners of the state. Now there are an estimated 30,000 swans across Minnesota.
Despite the surge in population, there’s still a lot that’s not known about where the swans travel in the winter.
Some stay in Minnesota, settling on open water on the Mississippi River in Monticello or along the St. Croix River.
Others have migrated to Iowa, Missouri and Arkansas. This research project, which will monitor 90 birds across the Upper Midwest, will gather more information about their migratory routes, and what kind of habitat they utilize.
“If we know they're migrating to an area in Iowa or Missouri, and that area is not currently managed for wildlife, we’d work with that state agency to improve conditions, so that the birds in that area are going to spend a safe winter,” said Moriarty.
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