The grouse’s thunderous take-off caught me by surprise — even though I was actually hunting them, I was still not prepared when it exploded from behind a log only ten yards away. I missed — not unusual for me since I probably missed more than I ever succeeded in bringing down. Unfortunately, the grouse hunting scenario just described isn’t happening as much these days, no doubt partly due to the fact that there are less people hunting them but also because there are other factors at work as well.

It’s long been known that grouse populations in Pennsylvania have been very cyclical — populations move up and down usually over a period of five to ten years. These fluctuations can be attributed to a number of different factors. Cold, wet springs following a harsh winter can result in lower numbers of successful hatches with many females and newborns often succumbing to the unfavorable conditions. Of course, vehicles hit some grouse, various predators take some and even natural disasters like floods and fires may kill some. Biologists feel, however, that hunter harvest of grouse is of very little significance when it comes to fluctuating populations.

Recently we have been hearing quite a bit about our declining grouse population and lower harvest numbers, and a couple of reasons are getting a lot of attention. One factor, that is easily overlooked, is our changing forest habitat. It’s probably overlooked by most of us because forests change so slowly that most of us just haven’t noticed. Cover is one of the most important factors affecting the size of a grouse population.

What does good grouse cover mean? Good cover encompasses things that provide natural shelter and protection from predators, as well as a good food source. Earlier in the century, Pennsylvania had an abundance of good brushy cover as a result of our extensive logging. Greenbrier thickets, stands of wild crab and hawthorn trees, abandoned apple orchards near thick cover and nearby stands of hemlocks and white pines and stands of aspens all add to favorable cover conditions. Of course, much of this kind of cover has disappeared today due to our maturing forests and lack of openings in the forest canopy.

If loss of favorable habitat were not enough to lower grouse populations, add to that another growing concern — mosquitoes! Nobody likes mosquitoes, I suppose except for bats, but it’s more than just their annoying, itching bite that causes concern. It’s well known that mosquitoes can carry West Nile virus. It can infect humans, but it can also infect and even kill grouse and other bird species. Research shows that grouse are particularly susceptible to the virus. Game Commission biologists have noted that each high West Nile virus year has been followed by a big drop in grouse numbers and other states are apparently also witnessing dropping grouse numbers.

The West Nile virus was first discovered at Scotia, which is the name given to a portion of gamelands in central Pennsylvania. Biologists are continuing their study and research in that area by collecting samples — 13,390 mosquitoes representing 25 different species have been collected. Could all of this lead to some type of mosquito control endeavor? Very possible, but exactly how that would be accomplished remains to be seen. Even if the threat of West Nile virus is reduced, we must still address the problem of aging forests to help boost grouse populations.

In the meantime, the January 2018 grouse season has already been eliminated and there could well be more to follow. Hopefully we will be able to overcome these problems so that we can hear that thunderous eruption of our state bird more often.