413 carcasses found in Gulliver
GULLIVER – The recent influx of dead waterbirds along the northern Lower Peninsula shoreline of Lake Michigan has now impacted the eastern Upper Peninsula. According to Common Coast, a nonprofit organization dedicated to studying loons, during two weeks in mid-October, a sevenmile stretch of beach near Gulliver amassed 413 carcasses, including 236 common loons.
Along a separate three miles of beach to the east of Gulliver, 72 common loons (among 96 total waterbirds) washed ashore during the same mid-October event. It was within this remote stretch of shoreline that the bodies of two colormarked loons from Seney National Wildlife Refuge were discovered during prior Lake Michigan dieoffs. One was a male who was banded as an adult in 1993 and was at least 17 at the time of his death in 2007, and a male who was banded as a juvenile in 2002 and who was eight when he perished in 2010.
Mirroring a pattern documented during previous outbreaks, all dead loons encountered in the eastern U.P. this fall have been breeding adults. According to Damon McCormick, of Common Coast, the waterfowl die offs have been occurring around Lake Michigan since 2006.
“Some years are quite bad, and some are mild,” he explained. “2007, 2010, and this year were all bad years. This trend seems to correlate with the lake water level and temperature.”
In 2012, the water level in Lake Michigan was low, McCormick added, and a warm summer led to warmer water temperatures.
October’s episode was preceded by a September mortality event that primarily involved horned and red-necked grebes. The season’s tally of 694 carcasses (nearly 100 birds per mile) comprises 247 common loons, 152 horned grebes, 98 red-necked grebes, 73 long-tailed ducks, 64 white-winged scoters and smaller numbers of ring-billed gulls, double-crested cormorants, herring gulls and red-breasted mergansers.
A number of agencies will be keeping track of the die-offs, explained McCormick, particularly the U.S. Geological Survey, which has crews walking the shorelines to monitor such occurrences.
Although collected specimens have not yet been tested for Type-E botulism, the circumstantial evidence strongly suggests that the toxin is responsible for most if not all of the deaths. According to the Michigan DNR website, Type-E botulism is a disease that results when a toxin, produced by the bacterium Clostridium botulinum, is ingested, causing paralysis. The disease has been associated with fish and water-bird die-offs on Lake Michigan in recent years.
Since the die-offs typically occur during the autumn months, McCormick said they are more likely to go unnoticed by residents. However, he noted that residents encountering such die-offs should keep an eye on pets, who may attempt to consume the carcasses. Information should also be provided to either the DNR or Common Coast.
For more information on the dieoffs, or to report an occurrence, contact McCormick at www.commoncoast.org or (906) 202-0602.