Loons, scoters, grebes, and piping plovers are among thousands of birds that can be found dead on the Lake Michigan shoreline. Type E botulism has been confirmed as the cause of death by the Michigan Department of Natural Resources (MDNR) in bird carcasses collected from numerous locations along the Lake Michigan shoreline. Each fall, reports of dead birds from Grand Traverse Bay to Sturgeon Bay are phoned in to the Tip of the Mitt Watershed Council office, where staff respond and work with Michigan Sea Grant and the MDNR to track bird and fish fatalities in affected areas.
According to the MDNR, botulism is a “paralytic condition brought on by the consumption of a naturally occurring toxin produced by the bacterium Clostridium botulinum.” Type E botulism is found in anaerobic (or low oxygen) environments, such as lake sediments, where it is taken in by fish. Affected fish experience a loss of equilibrium and exhibit unusual behavior such as swimming erratically or floating near the surface. These fish become easy targets and birds feeding on dead or dying fish are in turn affected. Great Lakes fish that have been affected by botulism include freshwater drum, smallmouth bass, rock bass, stonecats, round gobies, channel catfish, alewives and sturgeon.
Historic Outbreaks of Avian Botulism
Avian botulism was first documented in the Great Lakes in the 1960’s, but there were no confirmed cases in Lake Michigan between 1983 and 2006. Following this decades-long hiatus, botulism returned with vehemence, taking a heavy toll on migratory waterfowl with nearly 3000 dead birds reported from just Sleeping Bear Dunes National Park in 2006 and an estimated 8,000 dead birds turning up on the northern Lake Michigan shoreline in 2007. During the relatively cool summers of 2008 and 2009 with Great Lakes’ water levels rising slightly, the incidence of avian botulism dropped dramatically and few dead birds were reported. Unfortunately, the quiet was not to last. Scores of dead birds began to appear again on the northern shores of Lake Michigan in the fall of 2010, following a summer of warmer temperatures and a return to lower water levels.
Although uncertain, outbreaks may be linked to lake ecosystem disruptions caused by low lake levels and aquatic invasive species, such as quagga mussels, zebra mussels, and round goby. The bird kills also occur in surges, depending upon environmental conditions. Outbreaks pose little danger to people since most bird species affected are not typically eaten by people and thorough cooking destroys the toxin. However, everyone should take precautions if handling dead birds by using disposable gloves and washing thoroughly afterward. Anglers and hunters should avoid fish and waterfowl that are easy pickings due to strange behavior, such as lethargy and erratic swimming and all fish and game should be cooked thoroughly so as not to take any chances.
What you can do?
Remove dead birds and fish immediately, to prevent the spread of botulism, as the bacteria in the carcasses can serve as the source of outbreaks for months. Please review the following guidelines for handling carcasses and monitoring your beach area:
-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
-Assist with monitoring efforts. Contact us at 231-347-1181 to volunteer and help track the number and type of birds
Resources for Volunteer Monitors and Concerned Citizens
Botulism has been identified as a problem for fish and birds in Lakes Ontario, Erie, and Michigan. For more information about avian botulism in the Great Lakes visit the links below.
-Michigan Sea Grant Website – Avian Botulism Page
-Michigan DNR Website – Avian Botulism Page
-USGS Nation Wildlife Health Center – Avian Botulism Page
-Avian Botulism Monitoring – 2012 Report for Emmet and Charlevoix Counties
Since 2007, Tip of the Mitt Watershed Council has taken the lead to coordinate avian botulism monitoring in the Northern Lower Peninsula in an effort to better understand the underlying factors contributing to outbreaks. In the fall of 2012, the Watershed Council continued working with the Emmet County Lakeshore association (ECLA) and community volunteers to monitor outbreaks of avian botulism along the Lake Michigan shoreline in Emmet and Charlevoix counties. This is a report of their findings.
-Beached Bird Guide for Northern Lake Michigan
Prepared by Common Coast Research & Conservation, in association with the Grand Traverse Bay Botulism Network
© 2008 Common Coast Research & Conservation
This guide was developed to aid with the field identification of the most common waterbird species implicated in botulism E die-offs on northern Lake Michigan.
-Botulism Fact Sheet