DULUTH, Minn. (AP) -- Scientists suspect invasive species may be to blame in the deaths of hundreds of loons on Lake Michigan.
Last fall nearly 900 loons and probably more died while migrating south across Lake Michigan. Loons will begin their migration back north from the Atlantic and Gulf coasts in less than a month.
Minnesota Public Radio reports scientists with the U.S. Geological Survey suspect invasive zebra and quagga mussels create ideal conditions in Lake Michigan for the bacteria that produces botulism toxin, which works its way up the food chain into fish including the invasive round goby that are eaten by diving birds -- including loons.
Some loons that summer in Minnesota migrate via Lake Michigan. It's not clear how many have been affected because the state's loon population has been stable.