Lessons Learned from Ruffed Grouse Research in Idaho

By David Musil - Idaho Department of Fish and Game Idaho is rich with a variety of game birds, but one that has taken the backseat in popularity to quail, chukars and pheasants is the ruffed grouse, relegated to "camp meat" by some big game hunters. Yet a growing number of us realize and appreciate the challenges of hunting "ruffies." Unfortunately, little is known about Idaho's ruffed grouse, so during the past few years, Fish and Game biologists have been studying a population on the Boise National Forest north of Ola near Sage Hen Reservoir, an area known to hunters as Game Management Unit 32A. During the spring, male ruffed grouse perch atop downed logs and rapidly flap or "drum" their wings to attract females. This is the perfect time to take the pulse of the ruffed grouse population, by counting these "drummers." During boom years, counts in forests east of the Rocky Mountains can peak on average at 33 drumming males per square mile, whereas bust years average only 11 males; the cycle repeats every 10 years or so. In Unit 32A, numbers have held steady at around 13 males per square mile since 2007. It is assumed that the number of female grouse equals that of males, because they hatch at an even ratio. Females are harder to count because they are secretive, so biologists tried a technique of playing recordings of chicks in distress to attract hens into the open. "Peeping" chicks are irresistible to females, which instinctively want to help a crying chick. The technique yielded much lower numbers of females than drumming males. More work is needed on this technique before the conclusion is reached that there are truthfully fewer females. More study, involving the capture of hens to monitor nest success and chick survival, also needs to be done in the future. Male ruffed grouse aggressively defend their drumming logs from other males, so a mirror facing the drummer will lure him into a walk-in trap. During the study, 26 drummers were captured and radio-collared with transmitters to track their movements. These radio-marked males stayed within an average of 190 yards of their drumming logs year round, finding all they needed for food and cover within just over 100 acres of forest. When a male ruffed grouse died, he was replaced on the same drumming log by a different male the following year. Without radio-collar technology, it might have been wrongly assumed that it was the same drummer every year. Other data is being analyzed to determine whether suitable ruffed grouse habitat remains in short supply, a shortcoming that might explain why there are so few grouse compared to boom years back East. Hunters using the study area were interviewed, and it was discovered that 70 percent of them were primarily hunting big game; only 6 percent of these hunters said they would shoot a grouse if they saw one. Of the grouse harvested, 22 percent were taken incidentally by big game hunters and 69 percent by true grouse hunters. Only one of the radio-marked grouse was harvested over the past few years, so it appears that harvest rates are relatively low. About 66 percent of the grouse harvested were born the previous spring. This is typical, as young game birds are the least wary, and more abundant than adults. Young birds were about 20 percent lighter than adults and had stubby, partially grown tails. This is because opening day of the season is only 12 to 13 weeks from when most ruffed grouse chicks hatch, and they don't reach their full adult size before the season opener. Eastern states start hunting grouse after mid-September whereas Western states start before mid-September. In Idaho, opening day has been September 1 since 1990 and August 30 since 2010. Grouse harvest in Unit 32A peaks during the first week of the season and again right before deer season begins, so lengthening the season later into the winter would likely not affect grouse numbers. Moving the season a few weeks later at the beginning of the season likely would give juveniles more time to grow, but it is debatable whether this would increase grouse numbers. An experimental hunting season with a later opening date might help to solve this riddle. Unfortunately, research on Idaho's ruffed grouse has ground to a halt. Budgets are tight, and work is needed elsewhere on grouse in more dire condition, namely greater sage-grouse and Columbian sharp-tailed grouse. Perhaps one day, statewide ruffed grouse research will be launched, and expanded to include the other two forest grouse species, dusky grouse (formerly called blue grouse) and spruce grouse (sometimes called Franklin's grouse). Many lessons remain to be learned so Fish and Game biologists can more effectively manage this important Idaho resource. David Musil is a wildlife research biologist in the Magic Valley Region.