If you’ve been in the forests in Macon County in the early spring, you have probably heard something that sounds like a distant, old-fashioned lawnmower starting up – a thump-thump-thump that starts off slow and builds rapidly to a crescendo. Or maybe you have been hiking in the fall and almost had a heart attack when a medium-sized brown bird exploded underfoot and sailed into the brush.
The ruffed grouse (Bonasa umbellus) is the culprit in both cases. Or, if you are a mountain native of Social Security age, you might know them as pheasant or partridge; in the 1970s, in fact, the state hunting regulations also listed them as “mountain pheasant.”
Ruffed grouse are widely distributed across North America, ranging from central Alaska, across Canada and the upper Midwest, and across the northeast. Look at a range map, and you will see a peninsula extending down the southern Appalachians into Western North Carolina, east Tennessee, and north Georgia, almost as an afterthought. We are on the very southern edge of the range of a species that covers thousands of miles.
If you are a grouse hunter, you have likely made some dark jokes about hunting an endangered species. No, grouse are not endangered and are not likely to be, but they are on North Carolina’s list of “Species of Greatest Conservation Need.” In 2020, the Association of Fish & Wildlife Agencies (AFWA) reported that grouse populations have declined by 71% since 1989 in the southern Appalachians. Since 1984, the North Carolina Wildlife Resources Commission (NCWRC) has been conducting an annual survey of grouse hunters to gather data on hunting effort and success. Macon County is well represented in the survey, ranking third out of 22 counties in hunter participation.
Overall, the metrics for the number of grouse flushed and bagged have been on a fairly steady decline. Most dramatic is the increase in the number of hunts where no grouse are flushed; it is close to half over the past few years. The trend is the same for “drumming” surveys that the agency conducts in the spring. Basically, observers drive or walk survey routes and listen for the thump-thump-thump that male grouse make with their wings as they stake out breeding territories.
What is causing this decline? According to NCWRC Upland Game Bird Biologist Hannah Plumpton, “Grouse populations are primarily habitat driven.”
Most Western North Carolina forests are in the 80-120-year-old age range and are in the process of maturing after the widespread commercial timber harvesting of the early 1900s. Why does this matter? Because grouse are dependent on forest habitat in an early successional stage. Thick and brushy is the key. If a forest is open and pleasant to look at and easy to walk through, it probably is not a good grouse habitat.
Tree regrowth for about the first 30 years after some type of disturbance – such as wildfire, wind damage, timber harvest, or grazing/agriculture – provides the habitat essential for grouse. According to Plumpton, only about 5% or less of the forest stands in the Nantahala Game Lands are less than 30 years old.
Development on private land is also a factor in the equation. At least one house is situated now in the little hollow where I shot my first grouse.
However, another invisible, hard-to-pin down factor is contributing to the decline. In 1999, the West Nile Virus (WNV) was introduced into the United States. This mosquito-transmitted virus from Africa can infect humans, but it primarily affects birds. Crows, blue jays, and raptors are especially susceptible, but it can also be fatal to grouse.
Research projects in Pennsylvania and Minnesota have shown WNV to be a contributing factor in population declines. The NCWRC recently participated in a three-year, multi-state research project, and 11% of North Carolina birds sampled had WNV antibodies, meaning they had been exposed at some point and survived. Plumpton attributes this low prevalence to a high mortality rate from the virus. Most birds that are infected do not survive long enough to be sampled. The extent to which this virus is affecting the population is unknown.
Nature is not static. The interplay of habitat, weather and climate, predation, disease, and human activity creates a complex state of flux. Wildlife populations fluctuate annually and sometimes cyclically over several years, but a steady downward trend in a species is alarming to some of us.