The common loon, a beloved, iconic bird known for its eerily lonely, two-note call and its beautiful markings, suffered devastating losses along Lake Michigan’s northern shoreline this fall. Thousands of dead birds, mainly loons, washed ashore — from the Upper Peninsula down to Sleeping Bear Dunes National Lakeshore. A large percentage of the dead loons had just entered their first year of breeding maturity.
The reason for the die-off, which follows similar incidents in 2006 and 2007, isn’t fully understood. But it is suspected that it is driven by the food chain linking the loon to invasive species, specifically, the quagga mussel, the zebra mussel and the round goby.
... While the end result is a more aesthetically pleasing water column, the clearer water has allowed the sun’s rays to penetrate deeper, causing larger and larger algae mats to flourish on the bottom. As the algae mat builds upon itself and dies, it becomes anaerobic — depleted of oxygen — and type-E botulism bacteria develops.
The Oakland Press - www.theoaklandpress.com [includes video]
07 Jan 2012