Traverse City Record-Eagle


September 18, 2013

Researchers prep for avian botulism season

TRAVERSE CITY — Dead birds are nothing new to Julie Melottie. Her job requires her to see plenty of them, and the fall season often finds her sifting through flocks of feathered remains.

Melottie is a lab technician for the Michigan Department of Natural Resources wildlife disease lab in Lansing, where among other chores she conducts tests to determine whether birds have fallen victim to avian botulism.

She performed such a test on Tuesday to determine what killed bald eagles collected from Leelanau and Manistee counties.

She’s bracing for more tests, particularly among water birds like gulls and the iconic loon, if this season’s avian botulism outbreak is anything like what occurred in 2012.

“Last year was a big year it,” Melottie said.

Avian botulism killed tens of thousands of birds around the Great Lakes region since the 1950s, and more than 10,000 in 2006 and 2007 alone. Each year, corpses of infected loons wash up on the beach along the Sleeping Bear Dunes National Lakeshore in Benzie and Leelanau counties, often in late October and early November. Last year volunteers reported finding 580 dead loons along that stretch of Lake Michigan.

“You’ll see birds that are severely affected will have wings out, laying on the beach, and (their head will be) bobbing down or their bill will be touching down in the sand,” said Dan Ray, the project leader for avian botulism monitoring at Sleeping Bear Dunes.

Scientists believe invasive mussels may be to blame. Mussels filter lake water, which allows sunlight to penetrate deeper into the lake and cause thick blankets of algae to grow. As the lower layers of algae decompose, they provide the perfect environment for Type-E botulism bacteria to grow and produce a toxin.

The bacteria eventually enter the food chain, infecting the invasive gobi fish, which the birds eat.

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