Researchers are trying to solve the mystery of what caused the deaths of loons that died migrating across Lake Michigan, but they suspect zebra mussels may have played a role, MPR reports.
It's likely that at least some of the iconic birds that have died were from Minnesota, MPR says.
Scientists suspect invasive species could be to blame – specifically, invasive zebra and quagga mussels. The mussels trigger a complex ecosystem cycle that ultimately clears the way for a type of botulism that works its way up the food chain to the loons. The deadly toxin leaves the birds without muscle control, and in some cases, unable even to hold their head up out of the water.
The fast-evolving ecology of the Great Lakes Basin is due largely to invasive species that are devastating some of Michigan’s waterfowl, the Oakland (Mich.) Press reported. Thousands of dead loons washed ashore along Lake Michigan's northern shore last fall, the Press reports.
In one case last fall, biologists found 300 dead or dying loons and other birds on a single stretch of beach in northwestern Michigan's Sleeping Bear Dunes National Lakeshore, the Detroit Free Press reports.