Recent reports of dead loons and test results from the recovered birds suggest the West Nile Virus is making an increasing impact on the loon population.
The Veterinary Diagnostic Laboratory at the University of Minnesota confirm West Nile as the cause of death in two of three dead loons from northeastern Minnesota earlier this month. DNR Wildlife staff are receiving a small but noticeable increase in calls from people finding dead loons across northeastern Minnesota this summer.
West Nile Virus was first confirmed in Minnesota in 2002 and was documented as a cause of loon deaths in Minnesota as early as 2005. Mosquito bites are a common way to spread the virus. Health experts say most people and animals successfully fight off the virus and develop antibodies against future infection, but birds like loons and crows are especially susceptible to the infection.
Researchers are also attempting to discover the rates of infection among ruffed grouse.
While upsetting to those who love Minnesota's state bird, the DNR reminds residents that loons can die from a variety of illnesses and injuries, and individual bird deaths are a normal occurrence and not cause for alarm.
“Minnesotans love our loons and it’s concerning for people to find them dead. When we start seeing multiple birds dying on a single lake, we want to know about it so we can start tracking the information and determine when further testing is warranted,” said nongame wildlife specialist Gaea Crozier. “While there isn’t a way to treat the West Nile virus infection, knowing the cause can help us rule out other, preventable causes of mortality.”
Lake homeowners and other lake users who observe two or more dead loons on a single lake with no obvious injury or cause of death are asked to email the nearest DNR nongame wildlife staff to help them track what is causing the deaths.
More information about the DNR’s Nongame Wildlife Program and the Loon Monitoring Program can be found on the DNR website.