If U.S. Fish and Wildlife Service predictions hold, this year 92 million ducks will migrate south from their northern breeding grounds. Many factors will challenge the survival of these migrants, one of which is disease. According to Dr. Lynn Creekmore, hundreds of thousands of waterfowl are presently dying from avian botulism in flyway staging sites in southern Canada and the northern U.S.
Dr. Creekmore is a wildlife disease biologist at the U.S. Geological Survey's National Wildlife Health Center in Madison, WI. It is her job to monitor the occurrence of wildlife disease events in the U.S. Dr. Creekmore points out that avian botulism is the most serious disease of waterfowl in North America and quite likely the world.
The disease can produce massive annual mortality; during this year's fall migration, Canadian biologists are estimating the losses at one southern Saskatchewan lake to be as high as 300,000 to 500,000 birds. Also this year, at the Bear River Migratory Bird Refuge, along the shores of the Great Salt Lake, U.S. Fish and Wildlife Service biologists report waterfowl mortality from botulism has reached nearly 100,000 birds. Most recently, approximately 5,600 birds are believed to have died from botulism at a National Wildlife Refuge in Illinois. What is even more troubling is that the mortality is continuing and may not end until cold weather drives the birds further south.
Avian botulism is a disease of birds resulting from the ingestion of a paralyzing toxin produced by the bacterium, Clostridium botulinum type C. The toxin is closely related to botulism toxins A and B, which are responsible for a similar food-borne disease in humans. Affected birds lose coordination and show signs of paralysis of the legs and wings and labored breathing. In advanced stages of the disease, the birds cannot hold their heads up, and often drown or suff
Contact: Casey Stemler
United States Geological Survey