West Nile Virus Hits Michigan Ruffed Grouse

West Nile Virus Hits Michigan Ruffed Grouse

Photo credit: Keith R. Crowley/

In yet another case of “it was bound to happen eventually,” Michigan Department of Natural Resource (DNR) biologists have confirmed the presence of West Nile Virus (WNV) in five ruffed grouse either found dead or taken by hunters last fall in several northern counties.

Five birds gathered between August and October—two from Iron County and one each from Delta, Roscommon and Missaukee counties—had the disease, which is gradually moving further west from its East Coast introduction. Two of the infected grouse were found dead and three were harvested by hunters. All had the mosquito-borne virus, which weakens the birds and results in death for a large percentage of them.

Mosquitos also can infect humans with the virus, though most healthy people rarely show symptoms. A small percentage, however, becomes ill enough to require hospitalization and a few will succumb to the disease. It is especially difficult on the elderly and those with already compromised immune systems. Michigan had 43 hospitalizations in 2016 and three human fatalities from WNV.

Part of the difficulty in determining whether WNV is a threat to grouse is that ruffed grouse are well-known to have large swings in population. These cycles occur roughly every 10 years in Michigan and the other Great Lakes States, but some hunters and some biologists worry that they aren’t seeing the same level of “rebound” as in decades past, and they wonder if it’s related to WNV or some other disease. Rumors that WNV had decimated the grouse were rampant in my home state of Wisconsin last year when the increasing grouse numbers spring-drumming surveys predicted failed to materialize in the autumn woods.

And with one of the affected Michigan counties bordering northeast Wisconsin, it’s easy to see where the concern arises. It was not a concern before now because WNV had never been found in ruffed grouse in this neck of the woods.

“We’ve had West Nile Virus in Michigan since 2002,” said Thomas Cooley, a DNR wildlife biologist and pathologist at the Wildlife Disease Laboratory. “It’s the first year that we’ve seen it in grouse.”

West Nile Virus was originally found in the Nile River Valley in Uganda, Africa, in 1937 and soon after appeared in the western Mediterranean, Europe and southern Africa. The first U.S. case was reported in New York City in 1999. Since then the disease has gradually spread west, primarily through association with birds. Corvids such as jays, crows and ravens are especially susceptible, but most birds and mammals can host the disease.

The Pennsylvania Game Commission (PGC) has been at the forefront of WNV grouse research since the disease is present in all 67 of the state’s counties.  PGC, in conjunction with a WNV laboratory in Colorado, began research studies in 2014. Data pointed to a very low survival rate for young grouse infected in the first few weeks of life and dramatic health problems for nearly half the infected adult birds.

An article by lead researcher Lisa William in the September 2016 issue of PGC’s Game News highlighted the assistance hunters provided with the study by serving as “searchers” to help researchers find wild grouse eggs. The eggs then were shipped to the lab at Grouse Park where chicks could hatch and be raised in a quarantined environment.

“I drafted ‘Grouse Nests Wanted’ posters and sent them in April and May to organizations with members active in the springtime woods—the National Wild Turkey Federation, Trout Unlimited, Pennsylvania Audubon, mushroom clubs, hiking clubs and local birding clubs … ,” said William. “Ruffed Grouse Society members eagerly signed up to assist, as did experienced bird-dog handlers. I was humbled and overwhelmed by the outpouring of support. By my best count, more than 3,000 people were ready to help search.”

So far the ongoing study has determined that, as with many wildlife-related issues, habitat is the key.

“The most important activity that can be done is to maintain and create vigorous young forest habitat (primarily aspen) that is composed of multiple age-classes,” explained Al Stewart, Michigan DNR upland game bird specialist. “Michigan has high-value ruffed grouse habitat within areas of the state, especially in the Upper Peninsula. With West Nile Virus on the horizon, it will be even more paramount that we continue to focus on early successional forest management.”

The Ruffed Grouse Society agrees, issuing the following statement: “This WNV research is a call to action to create more high-quality habitat at a landscape scale. Young forest habitat creation and restoration is important due to the onset of WNV as an additional stressor to ruffed grouse populations, and land managers should focus on creating areas with diverse native food sources and thick protective cover.”

Ultimately, healthy birds living in high-quality habitat have the best chance of surviving a West Nile viral infection.

So what should you do if you harvest or come across a sick bird you suspect of having West Nile Virus or some other disease? The best bet is to immediately contact your local wildlife officials—biologists, game wardens or field techs—and get the bird into their hands as soon as possible. The Centers for Disease Control advises the following:

“State and local agencies have different policies for collecting and testing birds, so check with your state health department or state wildlife agency for information about reporting dead birds in your area. Wildlife agencies routinely investigate sick or dead bird events if large numbers are impacted. This type of reporting could help with the early detection of illnesses like West Nile Virus or Avian influenza (bird flu), known to cause death in birds. If local authorities tell you to simply dispose of the bird’s carcass (body), don’t handle it with your bare hands. Use gloves or an inverted plastic bag to place the carcass in a garbage bag, which can then be disposed of in your regular trash.”

Yeah, wear gloves. And even though I’ve also heard that properly cooked meat from an infected grouse is safe to eat, I’m not going to chance it.