Waterfowl die-off on Lake Michigan shores linked to type E botulism

Disease confirmed in Michigan’s Leelanau, Delta, Schoolcraft counties affecting loons, other migrating fowl.

These dead birds were located on the beach at Good Harbor Bay, Leelanau County. Photo: Dan Ray, National Park Service

These dead birds were located on the beach at Good Harbor Bay, Leelanau County. Photo: Dan Ray, National Park Service

Several species of waterfowl carcasses have recently washed ashore in Lake Michigan’s Leelanau, Emmet, Charlevoix, Delta and Schoolcraft counties. A team of volunteers has been monitoring places such as the Sleeping Bear Dunes, Northern Leelanau County region, the Garden Peninsula region and other stretches near the City of Manistique. The Michigan Department of Natural Resources Wildlife Disease Lab has confirmed type E botulism as the cause of death for these dozens and dozens of diving ducks and loons. Type E botulism causes a paralysis from the toxin released from the germination of the spore-like natural bacterium Closteridium botulinum; it is a recurring disease impacted by the changing Lake Michigan food web.

Since 2006, type E botulism has impacted some local and mostly migrating waterfowl passing through northern Michigan on their way to winter habitats. The recently killed birds include common loons, long-tailed ducks, white-winged scoters, red breasted mergansers, grebes and gulls. In Schoolcraft County alone, an estimate of 600 birds total were found along an 8 mile stretch of shoreline. Leelanau County estimates of around 250 birds, primarily long-tailed ducks, have come in during the last week of October 2016, and lesser amounts in Emmet and Charlevoix counties.

Many groups have loosely organized over the years to help gather data and bury carcasses so no other animals might be impacted. Researchers and volunteers from federal agencies such as the USGS National Wildlife Health Center in Madison, Wis., and National Park Service; academic institutions; state agencies such as the Michigan DNR and nonprofits have assisted in monitoring the hundreds of miles of Lake Michigan shoreline. The Sleeping Bear Dunes volunteers are nicknamed the “Bot. Squad VIPs” team:  fighting type e botulism since 2006. Information from summer beach volunteers showed a low dieoff until the recent kills. However, in Sleeping Bear Dunes a yearly high total was around 1500 birds during 2012 and so far this year the count is moderate.

Trained staff and volunteers are helping bury the carcasses after counting and noting location and species. The National Park does not collect or rehabilitate sick birds. People are encouraged to not touch the birds because of other possible diseases that might be present on the carcasses. In general follow these guidelines along the shore:

  • Do not handle dead fish or birds with your bare hands.
  • Properly dispose of carcasses by double bagging and placing them in the trash.
  • Beware of fish that are floating – if they are not fighting, they are likely not healthy and should not be consumed.
  • Do not eat undercooked or improperly prepared fish or waterfowl.
  • Hunters should never harvest birds that appear to be sick or are dying.
  • Do not let your pets eat dead fish or birds.
  • Look for carcasses at two peak times: in mid-late summer and in the fall and follow proper disposal methods.

If you are able to enjoy some fall beach walks in Northern Lake Michigan, recognize that there is a possibility of some waterfowl carcasses. Hopefully, the waterfowl will migrate through the region soon and the fall impact of type E botulism soon will be over for 2016.

Michigan Sea Grant maintains a web page with a variety of information on type E botulism outbreaks:  http://bit.ly/2e20DZU

Michigan Sea Grant helps to foster economic growth and protect Michigan’s coastal, Great Lakes resources through education, research and outreach. A collaborative effort of the University of Michigan and Michigan State University and its MSU Extension, Michigan Sea Grant is part of the NOAA-National Sea Grant network of 33 university-based programs.

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