An increase in annual loon deaths from a strain of botulism is sounding alarms among Michigan wildlife officials.
The Detroit News reports that it's been common over the years for common loon deaths to hit the hundreds but the numbers reached several thousand in in 2010 and 2012. Experts say invasive species such as mussels and gobies, and algae called Cladophora may be factors.
Botulism thrives in the Great Lakes sediments that have low oxygen. That sediment is picked up by bottom-feeding invasive species. When larger fish and birds eat the infected fish and mussels, the botulism moves up the food chain to the loons.
Other migratory birds have been affected but loon deaths tend to gain the most attention because their haunting call is so popular.