Common Loons were hit the hardest during the 2012 avian botulism outbreak. Photo: Wikimedia Commons
By Howard Meyerson
Joe Kaplan didn’t have to look far to find dead birds in 2007. Thousands had washed up on the northern Lake Michigan shoreline, from Sleeping Bear Dunes north across the Upper Peninsula. Carcasses littered the light-colored sands. It was a big year for avian mortality due to botulism, a potent toxin that causes paralysis and death.
“We wouldn’t know about these botulism outbreaks if it weren’t for birds washing up on the shore,” said Kaplan, a Michigan Audubon field representative and co-founder of Common Coast Research and Conservation, a Hancock-based nonprofit that studies Common Loons and helps in the cooperative effort to tally dead birds.
A lesser outbreak occurred in 2006, an incident that signaled significant change: botulism had not been seen on Lake Michigan since the 1980s, though outbreaks had occurred on Lakes Erie, Ontario, and Huron. The toxin has surfaced annually on Lake Michigan since then to greater or lesser extents. And scientists with the U.S. Department of Interior are now diligently working to locate the source and identify the chain of events that kills off birds by the thousands.
The 2007 toll was high. Staff and volunteers at Sleeping Bear discovered 1,135 dead birds along the park’s shoreline; there were 63 Common Loons. The lake-wide toll was 4,158 birds. Five years later, in 2012, the death toll was even higher. Beach monitors around Lake Michigan reported 4,386 dead birds, according to National Park Service regional staff in Ashland Wisconsin. At Sleeping Bear that year, 580 dead loons were collected.
“That was awful. It was devastating,” laments Sue Jennings, a wildlife biologist for the
Endangered Piping Plovers have been affected by avian botulism. Photo. USFWS.
national lakeshore. “We have 64 breeding pair of (endangered) Piping Plovers here. We provide nesting habitat for one-third of the entire population. So far, we know six chicks or adults have succumbed to botulism. It may be as high as eight. That’s a huge concern.”
Infected birds that die and wash up on a beach present a danger to other birds and animals that may feed upon their carcasses. National lakeshore volunteers that monitor beaches and collect carcasses wear protective clothing and gloves when handling them. Continue reading