January 16, 2013 - UNITED STATES - The rapidly changing ecology of the Great Lakes Basin, brought on in large part by non-native, invasive species, is causing devastation among Michigan’s waterfowl, especially common loons. 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.
 |
Photo courtesy of Common Coast Research and Conservation Dead loons lie along the Lake Michigan shoreline. |
Thousands Of Dead Birds Wash Up On Michigan's Shorelines.
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. Since 1988, when the first zebra mussels in Michigan were found in Lake St. Clair, the invasive mussels have been clearing and “cleaning” Great Lakes water columns by consuming plankton. 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. Gobies living in that environment at the bottom of the lake pick up the toxin produced by the bacteria. The gobies are then preyed upon by the loons and other fish-eating waterfowl, which become infected by the botulism. The toxin affects the bird’s nervous system and musculature, leaving it unable to fly. Soon, it can no longer keep its head aloft, and it drowns.
In just a 7-mile stretch of Lake Michigan beach near the Upper Peninsula town of Gulliver, 865 water birds showed up dead during a two-week period in October. Among these water birds were 302 common loons, 157 horned grebes, 142 long-tailed ducks, 103 white-winged scoters, 101 red-necked grebes and smaller numbers of ring-billed gulls, double-crested cormorants, herring gulls, red-breasted mergansers and common mergansers. All of the species are primarily piscivores, or fish eaters. That totaled an average of 121 dead birds per mile. Similar numbers were found further west, on beaches near the town of Manistique, as well as along the Lower Peninsula’s northern west coast and the Sleeping Bear Dunes National Lakeshore. It is believed these areas saw the most dead birds wash ashore due to prevailing wind patterns at the time. In the Sleeping Bear Dunes, 1,444 sick or dead birds representing 18 species were documented between June 21 and Nov. 20. Of those birds, 580 were common loons, with 422 found dead in October. Both numbers were the highest mortality rates ever recorded at the Lakeshore since accurate records began in 2007. Only 30 dead loons were recorded in 2011, and only 180 were recorded from 2007-2011. -
Advisor & Source.
Over 30 Birds Found Dead In Duson, Louisiana.
An odd discovery was made Tuesday in Duson. More than 30 birds were found dead, and as of now no one knows why. The birds had no visible injuries and were just scattered in an area next to a sugar cane field. "I came here this morning and saw birds all over the ground. One of them fell when I was walking around the property," James Wing said. When Wing found the dead birds his first thought went to a deadly disease. "I thought maybe it was West Nile. It was the first thing that popped in my head because they say, you see a dead bird you think it's West Nile," he said. Wing called a state biologist to come in and investigate. The biologist collected around 30 of the dead birds for testing in Baton Rouge. "We saw about a dozen of them that were ill. He said we'd probably see more until they could figure out what was the cause," Wing said. Despite all the stormy and unusual weather, the biologist from the Louisiana Department of Wildlife and Fisheries says it was likely not a factor in the deaths. Testing will give them a better idea of what happened by Thursday. -
KATC.
WATCH: Dead Birds in Duson A Mystery.