West Nile virus was detected last fall in three of 16 ruffed grouse that were found sick or dead and submitted by the public to the DNR.
West Nile Virus has proven to be a killer among other bird species like bluejays and crows. Humans and horses can also be affected by the virus. The virus is moved by mosquitoes looking for a blood meal to lay eggs.
DNR ecologist Mark Witecha, says there is no evidence to confirm that West Nile virus or any other factor is having population-level impacts on ruffed grouse in Wisconsin.
He says this sample size is too small to be accurate...
"..No conclusions could be drawn. Really what this confirms is that Ruffed Grouse in Wisconsin have been exposed to West Nile Virus. Really, I don't think that will come to much shock to a lot of folks. It's been detected in Ruffed Grouse populations in both Minnesota and Michigan in the past as well as some of the eastern populations as well...."
Ruffed grouse populations are known to rise and fall over a nine- to 11-year cycle, so declines are not unexpected, though the 2017 decline occurred before the cycle would typically predict. Witecha says the public should continue to monitor for sick or dead birds and if one is spotted to contact the local DNR wildlife staff. Witecha says the public can help the birds in another way...
"One study was done that found that West Nile Virus appeared to be affecting populations specifically in areas where there was poor quality habitat. What that would suggest is that by focusing on higher-quality habitat you might be able to mitigate some impact of the disease...."
DNR staff distributed 500 self-sampling kits to grouse hunters statewide with assistance from the Ruffed Grouse Society and the Wisconsin Conservation Congress as part of a multi-year regional study with Minnesota and Michigan. Ruffed grouse are a short-lived species with only 30 percent of the average adult population surviving