NEWS RELEASE Wisconsin Department of Natural Resources
May 21, 2018
MADISON – A region-wide effort to better understand West Nile virus in ruffed grouse is getting underway in Michigan, Minnesota, and Wisconsin. “In the Great Lakes Region, West Nile virus has been found in a small number of grouse with no known population-level effects at this point,” said Charlotte Roy, grouse project leader with the Minnesota Department of Natural Resources. “Still, we want to let hunters know we’re in the first steps of monitoring the virus, and we’re planning to do some limited testing of birds this fall.”In 2017, West Nile virus was identified in more ruffed grouse in the Great Lakes states than in the past. The virus has been present in Michigan, Minnesota, and Wisconsin for about 17 years.
West Nile virus has been documented in more than 250 species of birds; however, not all birds develop clinical disease from the virus. Corvids (including blue jays and crows) are very prone to illness and death from the virus, while other species may be less so or may not develop symptoms at all. Last year, Michigan had 12 positive cases of West Nile virus in ruffed grouse. Prior to 2017, only one positive ruffed grouse had been found in Michigan, and that was in 2002. The virus was confirmed in one ruffed grouse in the early 2000s in Minnesota, and is yet to have been detected in a Wisconsin ruffed grouse.
West Nile virus in ruffed grouse has become a topic of concern because of a recent study in Pennsylvania reporting that the virus may have contributed to population declines in areas of lower-quality habitat or where habitat was scarce. Michigan, Minnesota, and Wisconsin are in the early stages of planning to test samples from grouse this fall but at this point, there is no evidence that the virus is having a population-level impact in the Great Lakes region. “By monitoring birds at a regional level, we will be able to gain a better understanding of this disease in ruffed grouse,” said Kelly Straka, State Wildlife Veterinarian with the Michigan Department of Natural Resources.
Ruffed grouse are hunted annually by around 300,000 hunters across the three states. Preliminary reports from 2017 hunters were mixed across the Great Lakes region. While the virus could impact brood survival of grouse, other factors such as cold, wet springs during nesting and hatching; drought conditions; or habitat decline can also affect birds seen and harvested. Biologists in the region are optimistic that the great habitat for ruffed grouse in the Great Lakes states will help populations thrive despite the virus. “We are looking to hunters and outdoor enthusiasts to help us in this endeavor,” said Mark Witecha, upland wildlife ecologist with the Wisconsin Department of Natural Resources. “This is an excellent example of agencies and organizations taking a proactive approach and working together to expand our knowledge about WNV and ruffed grouse – we will be sharing updates throughout the process.”
Recently, the Midwest Association of Fish and Wildlife Agencies Health Committee held their annual meeting in Traverse City, Michigan. WNV was one of the topics for state wildlife health leaders. Over 25 wildlife health professionals from 13 midwestern states and Canada were in attendance. Individual agencies are currently reviewing ways they will be monitoring their grouse populations for WNV, and additional information will be shared when more details are determined.
Like humans, wild animals can be exposed to WNV and survive the exposure. Currently, there is no evidence of humans becoming infected by consuming properly cooked birds or by handling birds. Research has shown dogs can be infected but are very resistant to developing clinical signs of the disease and are considered an end host.