The Game Commission priority is to increase the number of birds entering the breeding population in mid-March to mid-April as a way to increase baseline breeding numbers. Certainly, some of these birds will die of natural causes prior to the breeding season, but current research indicates that monthly survival of grouse from January to March is 80-90% (with adult survival significantly higher than juvenile survival).

When we applied those survival rates to the number of grouse harvested in the late season from 2012-2015, we estimate that approximately 24,000 birds would have entered the breeding population over those four years if they had not been harvested in the late season.

Whether this increased survival is enough to make a noticeable difference in grouse populations is not yet known. However, there are several arguments for trying this approach:

1. Population connectivity. Both males and females are required to produce the next generation. Males in January through March are occupying a territory established in the previous fall to early winter. If males are removed from their established territories in late winter, these sites are not likely to be re-occupied in time for breeding. Most grouse make one major dispersal movement in their lives: juvenile dispersal in their first autumn (September). Therefore, the loss of both males and females degrades the connectivity and success of breeding populations.
2. Experienced breeders. More than half of birds harvested in the late season are adults. Males are occupying an established breeding territory and hens have already had experience in raising a clutch. Current data from Maine suggests that After-Second-Year hens have lower mortality during nesting than first year hens, which agrees with what we know about other game birds.
3. WNV immunity. Nearly a quarter (22%) of all late season birds tested had antibodies to WNV in 2015. These birds were exposed to the virus and survived. Based on research with similar species, survivors are likely to have lifetime immunity. They do not need to fight off the virus again, and their energy can be directed into breeding and raising a clutch. These are high-value birds to recruit into the breeding population.

Several states have shortened or closed their grouse season after grouse populations crashed. This framework represents an effort to proactively revise Pennsylvania’s season-setting process in an effort to respond to declines while we still have a functional statewide population.

Research on the impact of grouse hunting has returned mixed results depending on amount of available habitat, severity of winter conditions, level of natural (non-hunting) mortality, immigration into the hunted population from nearby population sources, level of hunting pressure, and harvest rate. The following background information was prepared by Game Commission Grouse Biologist Bill Palmer in 2003, and provides a nice overview of the relevant research:

[To find papers cited in this section, go to Google Scholar and enter the authors’ name(s), year and ‘ruffed grouse hunting’ or a similar search phrase].

Early Studies: Research on the effects of hunting on ruffed grouse populations began in the 1930’s in New York by Edminster and others (1937, 1947). After that period, most early research was conducted in aspen habitats at northern latitudes (i.e. Michigan, Palmer 1956, Dorney and Kabat 1960, Palmer and Bennet 1963). The Michigan publications included data from the period when MN closed grouse seasons (1944-47), and WI closed theirs (1945-47). While MI restricted their season, they kept it open during those years and the outcome showed that closing seasons did not do much to help grouse populations. They recovered in all 3 states. Fischer and Keith published their work from Alberta in 1974. All of these studies from the 1930’s into the early 70’s found no impact of fall hunting. Their recommendations for acceptable kill ranged from 25 to 50 % allowable harvest rate and most recommended longer fall seasons because they felt it would not increase the kill by much.

Research in the 1980’s: As hunting seasons were being liberalized, there were still concerns for grouse populations. Several studies done in the 80’s showed that grouse hunting mortality was additive (e.g. suppressed populations beyond the level of natural mortality) (see Bergerud 1985, Small et al. 1991). DeStephano and Rusch reported (1986) that hunting mortality during fall was additive but had little impact on grouse populations.

Other studies in the 1980s suggested that hunting mortality impaired subsequent breeding population size on heavily-hunted public hunting areas and in fragmented habitat (Kubisiak 1984, Rusch et al. 1984, Small et al. 1991). In 1988, Gordon Gullion in MN concluded that these consequences were greater from hunting mortality in the late season (Dec through Jan) compared to earlier in the season. Small and his associates (Small et al. 1991) suggested that on heavily-hunted public areas, ruffed grouse numbers lost to harvest are replaced by immigration from adjacent areas where hunting mortality is lower. They also suggested that where immigration is reduced due to widespread hunting pressure, or due to habitat loss and fragmentation, grouse numbers would be reduced. This interaction of public lands, hunting pressure, and fragmented habitat resulting in lowered populations (due to reduced immigration) was supported by Robertson and Rosenberg (1988) and Linden and Raijas (1986).

Research in the 1990s: The Appalachian Grouse Project, a multi-state study, investigated population dynamics and ecology of ruffed grouse in the southern and central Appalachian Mountains. Grouse were monitored at sites in KY, MD, OH, NC, PA, VA and WV (not all states in all years). Hunting mortality ranged from 0 to 34% (average 16%). Results showed decreased annual survival of grouse with increased hunting harvest rates (Reynolds et al. 2000). They also found this relationship to be weak in fall (Oct.-Dec.) and strong for late seasons (Jan.-Feb.). They suggested that fall hunting may have no effect on populations, while winter hunting may have a negative effect.

A more-focused look at hunting in VA, WV and KY (at sites with relatively low harvest rates) led the Appalachian study researchers to conclude that “a harvest rate of less than 20% in the southern and central Appalachians is compensatory (i.e. does not suppress populations). We believe current harvest rates can be maintained, but regional state agencies should not amend hunting seasons to facilitate higher harvest rates, particularly in light of the loss of habitat that is occurring throughout the region” (Ecology and Management of Appalachian Ruffed Grouse, 2011).

Additionally, the Appalachian study found evidence that hunting had an indirect effect on grouse survival: “Although we believe regulated sport harvest did not have a direct impact on ruffed grouse survival, there is evidence that disturbance from hunting (and other activities) influenced habitat selection and home range size of ruffed grouse (Whitaker 2003). Ruffed grouse (regardless of sex and age classes) made greater use of clearcuts and mesic bottomlands and had smaller home ranges in the absence of hunting. We believe this type of disturbance deserves consideration in the development of ruffed grouse hunting regulations and land management” (Ecology and Management of Appalachian Ruffed Grouse, 2011).

In short, information on the impact of hunting is mixed. Whether past studies found significant impacts of hunting or not, it is difficult to apply their findings to current Pennsylvania grouse populations which are at low abundance; during a period of low brood productivity and survival; with disease impacts occurring statewide, and; during a time when harvest shows low juvenile recruitment.

It is important to note that all large-scale studies of hunting impact were conducted prior to the arrival of West Nile Virus in North America. WNV shows strong indications as a significant mortality factor for Pennsylvania grouse. When natural mortality increases substantially, the ‘population math’ changes and the impact of hunting on that population may also change. In short, we have little to no clarity on the current impact of hunting on grouse. However, by using models to assess the Responsive Harvest Framework over time, we will get an indication of whether we are making a detectable difference in grouse populations and trends.

Ninety-eight percent of grouse hunters do not achieve the daily bag limit at any time during the hunting season, and 99% of grouse hunters harvest 5 or fewer birds in an entire license year. In 2015-16 license year, avid grouse hunters (Game Commission Grouse Cooperators) hunting a cumulative 2,292 days, achieved bag limit on just 4% of hunt days. Thus, all evidence suggests that reducing bag limit would not increase the number of birds surviving into the breeding population. Additionally, more hunters prefer to see season length reduced rather than bag limit, according to the results of the 2015 Grouse and Woodcock Hunter Survey.

Forty percent of late season hunting and harvest occurs in the first week, December 26 – January 1. If the late season were shortened to one week, some hunters who normally hunt later in January would shift their hunting to the open week. Estimating conservatively, we would still be harvesting 50% (or more) of the birds normally harvested. To support recovering populations in all regions, the goal of grouse season-setting is to minimize late season harvest to increase the likelihood that these birds are carried into the Spring breeding population. By shortening the late season to one week, we would be inconveniencing hunters while not retaining the number of breeding birds we need. Likewise, shortening the late season by two weeks (and leaving 2 weeks open) would not measurably increase grouse abundance because most harvest occurs during the first two weeks (as shown by Game Commission research conducted in the 1980s).

For the first time in PA, the RHF uses a split zone approach to season setting. For purposes of season setting, the Northern Management Zone will be comprised of WMUs 1B, 2F, 2G, 2H, 3A, 3B, 3C. The Southern Management Zone will be comprised of WMUs 1A, 2A, 2B, 2C, 2D, 2E, 3D, 4A, 4B, 4C, 4D, 4E, 5A, 5B, 5C, 5D. This change is due to the differential forces acting on grouse populations in northern versus southern counties: 1) different population trends; 2) differential harvest pressure, and; 3) differential disease prevalence. In the Game Commission 2015 Grouse and Woodcock Hunter Survey, 58% of more than 2000 grouse hunters indicated that they supported a split zone approach.

For more information on the RHF and a map of the Northern and Southern Management Zones.

The late season is the season which most impacts the breeding population. In the late season, we are harvesting survivors. They have survived earlier hunting seasons and they have survived the rigors of winter to date. Also, late season harvest disproportionately removes adult birds (i.e. experienced breeders) (October adults = 34% of harvest; November adults = 51% of harvest; December adults = 57% of harvest; late season adults = 56% of harvest). Late season birds are just 8 to 12 weeks from the reproductive season. The goal for closing the late season when populations are low is to maximize the number of birds carried over into the breeding population. Finally, historic research across multiple states has indicated that population-level impacts from winter hunting are stronger than those of fall hunting.

In our 2015 Grouse and Woodcock Hunter Survey, the Game Commission asked about factors that limited participation in grouse hunting: 71% of hunters stated that low grouse populations limit their participation while just 34% stated that lack of time limits participation. Based on hunter input, lack of grouse is a much more significant barrier to grouse hunting than lack of time. The Game Commission remains sensitive to the difficulty of allocating and prioritizing free time across a variety of hunting seasons and personal responsibilities. However, hunter survey data suggests that we can best serve grouse hunters by managing for higher grouse populations. To assess impact on grouse hunting participation, we will monitor any changes that occur in statewide number of hunters and days afield relative to available days.

The decision to open or close seasons is made annually by the Game Commission Board of Commissioners. By implementing a responsive harvest framework (RHF), the grouse season will change in response to changing grouse populations. When grouse abundance and/or production improves, Game Commission has a mechanism in place to adjust the grouse season.

To assess the impact of this new RHF approach, models will be developed that incorporate new data each year. One model will assume that the RHF is making no detectable difference in grouse populations or trends. The other will assume that the RHF is contributing to detectable changes in populations or trends. By seeing which model competes best over time, we should get a sense of whether the RHF is working.

Although the Grouse Plan was ambitious, and resources for grouse management are quite limited, the Game Commission has made (and continues to make) significant progress on plan deliverables. Implementation of the Game Commission’s Ruffed Grouse Management Plan is well underway, with progress made on 20 of 23 management objectives (87%) to date.

The possibility of changing the grouse season was identified under the Population Objective of the Grouse Management Plan, which stated that season structure would not be changed unless warranted by research results:

Grouse Management Plan Strategies:
1.4 Except for any experimental manipulations needed to meet research objectives, annually recommend a grouse season maintaining current length, timing, and statewide structure until research results are available.

1.5 If warranted based on research results, recommend adjustments to season length and/or bag limits at appropriate scale (statewide, grouped WMUs, or individual WMUs) to avoid additive mortality from harvest.

Recent analysis of brood surveys, hunter flush rates, impacts of West Nile Virus, and low juvenile recruitment into the fall harvest are all research results that triggered the recommendation for a season modification. These research results clearly show that a significant change has occurred in grouse population demographics since the 1980s (when the current season structure was enacted) – and more importantly since the early 2000s (when WNV entered the state).

Additionally, progress on the Habitat Objectives of the Grouse Plan is an annual priority of the Game Commission. Pennsylvania’s forest management is already more active than most or all States in the Mid-Atlantic, and we are still increasing activity. For the fiscal year (FY) ending in June 2022 (FY 2021), Game Commission foresters accomplished 23,519 acres of actual harvest. That is more than a 50 percent increase from the average acres impacted from FY 2010 through FY 2020 and represents the recent efforts of our staff, which have increased timber offered for sale every year since 2011. Sale offers, bids and contracting, all of which take time, are now showing results on the ground. We are continuing to increase our commitment by hiring additional Forestry staff. 

When WNV first moved though the US, people found dead crows and blue jays because these species were abundant and live near human settlements. They also lack the incredible camouflage of a grouse. This makes the likelihood of finding a carcass greater for jays and crows. To make matters worse, grouse likely die from WNV in summer, when few hunters and bird dogs are moving through grouse coverts. In the Lake States, where grouse seasons tend to open a month earlier than in PA – closer to the active WNV period - hunters have found sick grouse in the woods. Finally, a dying grouse is an easy target for predators, so the window for finding a sick grouse or carcass is very brief.

Grouse do not infect other species. The virus is spread by the bite of an infected mosquito. The Game Commission lab study showed that the virus did not pass from grouse to grouse kept in direct contact with one another. This indicates that a sick grouse is not likely to pass the virus to another animal, though animals inhabiting the same area may be vulnerable to WNV+ mosquitoes that inhabit that area.

Birds harvested in October-January were most likely exposed to WNV during summer (July through mid-September). Even those who sickened in summer should not have active virus in their blood at the time of harvest. Therefore, hunters and hunting dogs should not be at risk from harvested birds. Hunters should follow the same advice given for any game: use precautions during field dressing and cooking.

Determining susceptibility of a wild species to a pathogen requires a multifaceted approach because one test alone cannot determine susceptibility or population impacts. Rather, the following approaches are used collectively: 1) Population monitoring; 2) Experimental infection trials; 3) Passive surveillance (mortality investigations); 4) Active surveillance (antibody or viral surveys of a population); 5) Population and Disease Modeling (if data are available); and 6) Other options including Sentinels, Model Species, etc.

For ruffed grouse in Pennsylvania, population monitoring shows a strong correlation between the virus and population declines at regional and statewide scales. This led to further research steps #2-5 above. [See Stauffer et al 2018: Journal of Wildlife Management, Nemeth et al 2017: Journal of Veterinary Pathology, and/or the Pennsylvania Game Commission’s Ruffed Grouse web page.]

For wild turkey and wild ring-necked pheasants, the Game Commission has been acquiring abundant passive surveillance data (testing sick and dead birds found on the landscape). Both species exist in areas where WNV is known to circulate, so they may be exposed to the virus. To date, neither species has tested positive in Pennsylvania, and only two states (Michigan and Missouri) have reported any mortality of wild turkey due to WNV. This suggests wild turkeys may be very slightly susceptible, but NOT highly susceptible to the virus. Being large, visible birds, if they were susceptible and experienced high mortality we would see many sick birds on the landscape, just as sick and dead crows are found on the landscape during active WNV seasons.

This is where experimental infection and other approaches enter the assessment. WNV has a wide host range, i.e. many species are susceptible to infection, but susceptibility to clinical disease varies by species. Some species (wild turkey and pheasant) seem to tolerate the virus well; others suffer high mortality (ruffed grouse). Similarly, many songbirds and raptors are affected by WNV, while others seem to be unaffected. [See George et al, Proceedings of the National Academy of Sciences, Nov 2015.]

An experimental study on domestic turkey poults, where only one of 12 turkeys died after being inoculated with or exposed to WNV, suggested that WNV lacks the potential to be a major mortality factor in turkeys, and turkeys are not a significant amplifying host for infecting mosquitos. Domestic turkeys were a model species. If we conduct a laboratory study on wild turkeys, we may detect a different mortality level, but again, passive surveillance suggests WNV mortality is highly limited and sporadic. Wild turkey populations are declining in some areas, but are booming in other areas, unlike the across-the-board declines of ruffed grouse. Considering the widespread distribution of WNV, and the careful population monitoring done by state agencies, wild turkey declines would be obvious if they were highly susceptible to the virus.

The above also holds true for pheasants and woodcock; WNV mortality may occur on a limited and sporadic basis. But if WNV mortality among pheasants was high, we would detect more mortality in farm-raised unvaccinated birds and in states with large wild pheasant populations. If WNV mortality among woodcock was high, population declines should be evident because woodcock occur specifically in wet habitats. For bobwhite quail, work is being conducted in west Texas where they’ve seen WNV antibodies in other quail species. Researchers are looking at bobwhites to determine if the virus is affecting them and if it may be contributing to quail declines.

In summary, wildlife biologists are not seeing population impacts to wild turkey, woodcock or pheasants from WNV that we see for ruffed grouse. However, there is interest in pursuing future active research, as time and resources permit. These investigations should involve a multifaceted approach that include research steps 1-5 above, with an emphasis on experimental infection trials, passive (hunter-harvested field surveys) and active surveillance.

Cold, wet springs may reduce brood survival due to decreased insect availability and outright exposure. Warm wet springs may increase invertebrate (i.e. grouse brood food) populations, but also benefit some mosquito species. Hot dry summers benefit mosquitos that carry WNV because they breed in stagnant water. While managers can indirectly monitor the effects of weather on grouse production using existing surveys, this is a factor we can only react to – not control.

Like other game bird species, a major mortality source for grouse is predation. While it can be easy to conclude that reducing predator numbers is the best way to help grouse, that may not be the case. Many studies have shown that controlling predators is largely ineffective, and that large-scale predator control efforts are neither scientifically-justified nor publicly-acceptable. Additionally, grouse may also experience high mortality from non-predator-related causes, such as West Nile virus disease. Therefore, putting high quality cover in areas with low disease prevalence is the best way to shield grouse from both disease and predator related mortality. 

The Game Commission and DCNR actively manage tens of thousands of acres per year to improve forest conditions and create the thick young forest required by grouse. Pennsylvania’s forest management is already more active than most or all states in the Mid-Atlantic, and we are still increasing activity. For the fiscal year (FY) ending in June 2022 (FY 2021), Game Commission foresters accomplished 23,519 acres of actual harvest. That is more than a 50 percent increase from the average acres impacted from FY 2010 through FY 2020 and represents the recent efforts of our staff, which have increased timber offered for sale every year since 2011. Sale offers, bids and contracting, all of which take time, are now showing results on the ground. We are continuing to increase our commitment by hiring additional Forestry staff. This activity will support populations of many declining species that require young forest habitat.

Unfortunately, large-scale management of Pennsylvania forests is beyond the control of public agencies. Roughly 70% of PA forest land is privately owned and most of those owners are NOT making grouse habitat. Many private landowners are loving their forests to death by neglecting them through hands-off management. Others are slowly degrading the habitat quality of their forests by inappropriate management: high-grading, diameter limit cutting and ‘select cuts’ that remove only a few large trees from a stand all severely diminish forest health, productivity, and habitat quality.

Finally, the need for more grouse habitat is a long-term solution to a long-term problem. Forest acreage managed today takes a number of years before it becomes prime grouse habitat. The record low grouse abundance seen in the 2014-2016 license years, coupled with the record low summer observations in 2017, indicate that short-term intervention is warranted to stem ongoing declines and support recovering populations.

If you are passionate about grouse and want to assist, please educate your neighbors, your hunt clubs and fellow hunters about the value of active and responsible forest management. Even well-intentioned landowners can be overwhelmed with choices when it comes to managing their forests. Penn State’s Forestry Extension offers many tools and workshops to assist private landowners: http://ecosystems.psu.edu/research/centers/private-forests

For landowners with a particular interest in grouse and other wildlife of the young forest, this site is a clearinghouse of online resources to help you with your education efforts: http://youngforest.org.

For assistance with forest management and wildlife habitat planning, consult with a: Game Commission Private Lands biologist.

and/or DCNR Service Forester.

Recommendations for season and bag limits are made to the Game Commission Board of Commissioners (hereafter 'BOC') each year, followed by a public comment period and BOC final vote. This allows season changes to be made in response to new research and population data obtained each year. The duration of the late season closure is unknown. Re-opening of late season opportunities will occur when grouse population indicators improve.
A ‘responsive harvest framework’ (hereafter ‘RHF’) has been developed that will provide a mechanism for expanding and restricting the late season as new population information is received. This framework relies on indicators of abundance (hunter flushes per hour), production (grouse summer observations) and disease risk (West Nile Virus surveillance). This framework relies on a split zone approach to season-setting because northern and southern grouse populations face differential hunting pressure and disease risk, and are exhibiting different population trends. 

​A responsive harvest framework is used for some migratory game birds (doves and woodcock) as a safeguard to prevent over-harvest. A RHM framework incorporates abundance and productivity measures into season-setting decisions so that seasons and bag limits respond to changes in populations. Thresholds and triggers are identified that direct population managers to set liberal, moderate, or conservative seasons.  When the population exceeds certain thresholds, the season is lengthened. If population indicators drop below certain thresholds, the season is restricted. The benefit of a responsive harvest framework is that season-setting is consistent from year to year, responsive to the grouse population, and transparent to the public.

The primary research priority is to identify factors that influence WNV prevalence in grouse habitat (such as mosquito species involved,  elevation, slope, distance from standing water, vegetation characteristics). By understanding the distribution of vector mosquito(es) in grouse habitat, we may find information we can exploit during habitat management. 

​(Information taken from Devers 2005: Population ecology of and the effects of hunting on ruffed grouse (Bonasa umbellus) in the southern and central Appalachians)