Hundreds of common loons, ducks, grebes and gulls are dead and others are at risk following the return of Type E botulism this fall.
The state Department of Environmental Conservation said they have found from 200 to 300 loons washed up on shorelines in Jefferson and Oswego County, the largest such outbreak for the lake region since 2006. The DEC said bird carcasses did not wash ashore until late October, with most surfacing in the last two weeks.
In past years, mortality events have not occurred much later than the third week of November, which the DEC said led it to believe there may not be many more deaths, although carcasses may continue to wash ashore. According to a DEC news release, Type E botulism is caused by a bacterial toxin produced by Clostridium botulinum, a widespread bacterium in the sediments of the Great Lakes.
Certain environmental conditions cause this strain of Clostridium to produce a toxin that can spread through the food web of the lakes. First documented in waterbirds from Lake Michigan in the 1960s, Type E botulism was recorded irregularly for three decades in the lower Great Lakes.
The department attributed the problem to non-native round gobies and quagga mussels. The department said in its news release that the public is encouraged to report dead birds to their regional offices. Carcasses contain small amounts of toxin and pose some threat to animals that feed on them. DEC has removed carcasses from portions of state-owned shoreline.
Shoreline residents are encouraged to bury carcasses if feasible. To report dead birds found in Jefferson County, contact the DEC at 315-785-2263; to report birds found in Oswego or Cayuga counties, contact the DEC at 607-753-3095, ext 247.