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Avian E Botulism

Spring-Summer 2008

This last fall, northern Lake Michigan was especially hard hit with the toxic effects of Type E botulism also known as avian botulism. The count is approximate but the mortality bird number being circulated is 8,000 with 2,000 being identified as loons. Many of our native waterfowl as well as migratory birds such as the white-winged scooter, horned and red-necked grebes, mergansers, long–tailed duck, and piping plovers were caught in a dangerous anaerobic soup. According to Ken Hyde, Wildlife Biologist from Sleeping Bear National Park, they watched as the warmer Lake Michigan water mixed with the large mats of cladophora that rolled along the lake bottom. Although this type of botulism is native to the Great Lakes, the decaying cladophora mixed with botulism infected gobies were eaten by these birds. Neuro toxins are released which paralyze the birds in the water. There are many remaining questions for researchers such as whether the infected area was localized in portions of Lake Michigan or wide spread.

What is the property owner to do if they find a dead bird on their beach this spring/summer? According to Mark Breederlander from SeaGrant the following steps should be taken:

  • Least desirable is leaving the carcass on the beach. Toxins can be spread to scavengers as well as leaching back into the water and re-infecting zebra mussels along the shore.
  • Keep family pets away from carcasses and birds that may be on the shoreline exhibiting unusual behavior.
  • Remove and double bag the carcasses and take to the Transfer Station. As with any dead animal, rubber gloves are to be used and stand so wind is downwind when picking up.


  • Bury the carcass 2 feet below ground, away from water sources and in an area that will not be dug up.
  • Botulism is destroyed in sunlight and fresh air, but some botulism spores may remain.
  • You will not get botulism by swimming in Lake Michigan.
  • DO NOT eat raw fish from Lake Michigan. Fish or birds that are displaying unusual behavior should never be consumed.
  • There is a very real possibility that this die off will occur again in October/November of 2008, if conditions continue. Some shoreline birds may be affected this summer season.
  • Brian Mastenbrook, from the Michigan Department of Natural Resources, is to be notified with any banded birds. His office number is (989) 732-3541 ext. 5430.
  • The DNR will be involved in the coordination of surveys and reporting. Shoreline owners are going to be asked to participate in the identification and record mortality. Ken Hyde from Sleeping Bear will provide a visual guide to carcass identification for those birds that have been in the water for an extended period of time. Swans that have black beaks are Trumpeter and also need to be reported. This carcass guide is in production and other information and links can be found on line at
  • This fall, concern was high regarding whether Beaver Island’s 5-7 breeding pairs were in the count. Only the spring would bring an answer to our loon population. A sigh of relief came when loon calls were noted on Greene’s Lake and the harbor this spring. Sleeping Bear biologists are encouraged and have reported Piping Plover sightings and returning loons.
  • Jacque LaFreniere, our “Loon Lady” will be organizing the shoreline identification project and is in need of volunteers to monitor our beaches this summer and fall. If you are planning on being on Beaver Island for an extended period of time, please consider contacting Jacque to help. Jacque’s e-mail is: or (231) 448-2220.

– Pam Grassmick

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