Parasite carried by snails likely culprit
MEMPHIS, Tenn., November 7, 2007 – An estimated 3,000 scaup and several hundred coot were found dead on Minnesota’s lake Winnibigoshish. Waterfowl hunters and officials from the Minnesota DNR first spotted the dead and dying birds on the west shore of the lake on October 28. Initial reports indicate the birds died of a trematode, or small intestinal parasite. The parasite is not a threat to humans, but experts recommend that hunters do not consume sick waterfowl.
“The parasite requires intermediate hosts to complete a complex life cycle before it infects the final host, in this case scaup,” explains Dale Humburg, Chief Biologist of Ducks Unlimited. “When waterfowl eat an infected snail, the trematodes attack the birds’ lower intestines causing ulcers and hemorrhage and resulting in severe blood loss. The birds can be infected in less than a day and die in three to eight days.”
The scaup die-off is another indication of problems facing scaup populations in recent years. Average breeding populations exceeded 6 million during the 1970s and early 1980s but have declined to less than 4 million for most of the last decade.
“There is no single cause implicated in the decline,” says Humburg. “Ducks Unlimited, along with the rest of the waterfowl management community, has been aware for some time of the scaup decline and is actively involved in the research needed to determine the causes.”
Wetland losses and degradation, lower hen survival and nest success, the impact of contaminants and parasites, poor body condition during migration, and harvest impacts all have been studied. Humburg says a comprehensive solution is required to reverse the downward trend in scaup numbers.
“Ducks Unlimited has already focused considerable attention on wetlands that are believed to be important throughout the scaup’s annual cycle,” says Humburg. “These include the key breeding areas such as the western boreal forest, important migration areas such as the Great Lakes, and southern wintering areas including the Gulf Coast.”
This inclusive approach to the management of scaup and other ducks is fundamental to the future of waterfowl and waterfowl hunting.
With more than a million supporters, Ducks Unlimited is the world’s largest and most effective wetland and waterfowl conservation organization with almost 12 million acres conserved. The United States alone has lost more than half of its original wetlands - nature’s most productive ecosystem - and continues to lose more than 80,000 wetland acres each year.
Contacts:
Laura Houseal, (901) 758-3764, lhouseal@ducks.org
For a specific report on the Minnesota die-off and on research by the U.S. Geological Survey and others, see: