“By the late 1800s, Trumpeter Swans were extirpated from….” is a common phrase regarding the history of swans in the eastern 2/3s of the lower 48 states. The Upper Peninsula of Michigan was no exception. Now, Trumpeter Swans are sharing the same nesting islands with Common Loons at Seney National Wildlife Refuge (Seney or Refuge) and the swans are expanding their range beyond refuge boundaries.
Established in 1935, Seney is located in the east-central portion of the Upper Peninsula of Michigan between Lake Superior andLake Michigan. The Refuge encompasses 95,238 acres, of which three quarters are classified as wetland habitat. Prior to the existence of the Refuge, there were no named bodies of water in the area that was known as the “Greater Manistique Swamp.” The Refuge’s primary focus was waterfowl management, so open water bodies were needed. Over the next 20 years, the Refuge staff, Civilian Conservation Corps (CCC), and Works Progress Administration Crew (WPA) worked to convert the “Swamp” into a series of pools and dikes to provide habitat. As a result of their efforts, the Refuge now has 27 man-made pools and potholes, beaver ponds, and ditches that account for 7,456 surface acres of impounded water, 7.8 percent of the total acreage.
The Refuge pool system provides critical habitat for the swans. Due to the natural topography, pine islands were formed when the pools were flooded and make excellent nesting areas that provide protection from predators. The average depth in the pools is 4 – 6 feet, so the shallow open water makes submergent vegetation accessible for feeding. Aquatic plant species such as naiad (Najas quadalupensis), wild celery (Vallisneria americana), waterweed (Elodea canadensis), Chara spp., and pondweed (Potamageton spp.) are abundant enough to support a growing swan population. Other key attributes that make Seney ideal for swans is that the landscape is mostly ecologically intact and isolated. In addition, the area is unaffected by urban influences (e.g. power lines) and there are no lead shot issues due to a lack of waterfowl hunting history. Both of these have been cited as important causes of mortality for other Interior Population swans.
In 1991, History Program of the Michigan Department of Natural Resources, in cooperation with the US Fish and Wildlife Service (FWS), started a program that planned to reintroduce Trumpeter Swans toMichigan. Ten 2-year-old Trumpeters were placed on the pools to begin the program. Over the next 3 years, a total of 44 birds was released. The swans originated from eggs collected inAlaskaand subsequently hatched and hand-raised at the Kellogg Bird Sanctuary on the campus ofMichiganStateUniversitynearBattle Creek,Michigan. The success of the program came fast when, in 1992, one of the pairs released in 1991 nested, hatched, and successfully fledged two cygnets. Former refuge manager Mike Tansy (1989-2001), who recognized the potential of Seney in the reintroduction of Trumpeter Swans to the State ofMichigan, played a crucial role in getting the program started.
Success continues as the number of white birds and cygnets increases. From 2005 to 2010, an average of 228 adults and subadults used the Refuge (Figure 1). During that period, the Refuge has an average of 32 nesting pairs that hatched an average of 87 cygnets. The swans continue to explore areas beyond the boundaries of the Refuge and establish new territories. Although it took over 100 years, Trumpeter Swans are once again a part of theUpper Peninsulalandscape.
Figure 1. Peak counts of white birds at Seney National Wildlife Refuge, Seney, Michigan, 1991-2010.
*Dave Olson has been working with Trumpeter Swans since 2000. He was the biologist at Red Rock Lakes NWR, Montana, from 2000 to 2002 and at Seney NWR, Michigan, from 2005 to 2009. He is currently the Assistant Migratory Game Bird Coordinator for the Mountain-Prairie Region of the FWS where one of his tasks is to coordinate Trumpeter Swan management for the region.
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