Itasca County encompasses nearly 3,000 square miles. How many ruffed grouse exist within its borders is anyone's guess — literally. But whatever the number, it's fair to assume a reasonable percentage have been exposed to Eastern Equine Encephalitis (EEE), a virus that until this fall had never before been detected in a Minnesota wild animal.
In October, hunters in Itasca County found and/or shot three ruffed grouse that didn't behave, or appear, "normal.''
One hopped repeatedly when pursued by a dog, instead of flushing and flying away. The other two were shot. But upon inspection they appeared to be in poor health.
All three grouse were submitted to Minnesota Department of Natural Resources (DNR) wildlife officials. Subsequent tests at the University of Minnesota showed two of the birds, and possibly the third, were suffering from EEE, a mosquito-borne virus that most commonly afflicts horses but also can target other species, including people.
Six Michigan residents died this year after contracting the virus.
In Minnesota, DNR wildlife biologists and disease specialists have been on the lookout this fall not for EEE in ruffed grouse but for West Nile virus. Their vigilance follows a disconnect that emerged in the last decade between springtime grouse-population drumming counts and the number of birds hunters see and harvest in the fall.
Historically, drumming counts and fall bird sightings and harvests have correlated as an index that fairly accurately tracks the rise and fall of the grouse's 10-year population cycle.
The most recent evidence that the link between the spring counts and hunters' fall ruffed-grouse sightings and harvests is broken occurred in 2017. Hunters that year expected a banner fall season after record- or near-record-high spring drumming counts. Instead hunters had one of their worst seasons.