Experts ask: Where have all the grouse gone?
QUANDARY: Anecdotal reports from hunters point to a poor harvest this fall, and biologists aren't sure why. Where have the grouse gone? That's the question several ruffed grouse biologists and grouse hunters tried to answer at an informal meeting...
QUANDARY: Anecdotal reports from hunters point to a poor harvest this fall, and biologists aren't sure why.
Where have the grouse gone?
That's the question several ruffed grouse biologists and grouse hunters tried to answer at an informal meeting Wednesday in Grand Rapids.
Spring drumming counts in Minnesota indicated the statewide grouse population was up about 30 percent over last year. This was the third year in a row of increasing drumming counts, a sign that the state's grouse population was on its way toward the high point of its 10-year population cycle.
But most hunters are not finding the number of birds that such a drumming increase would have foreshadowed. And at the 26th annual National Grouse and Woodcock Hunt, held Oct. 9-12 in Grand Rapids, the ratio of this year's young grouse to adult females was well below the long-term average.
Biologists from the Ruffed Grouse Society, the Minnesota Department of Natural Resources and the University of Minnesota joined a handful of grouse hunters Wednesday to discuss possible causes for the modest hunter success this fall.
"I've heard the same mixed bag of reports," said Mike Larson, the DNR's grouse biologist in Grand Rapids. "Probably more poor than good."
The ratio of immature (hatch-year) birds to adult females was about 4 to 1 at the national hunt this fall, according to hunt records. The25-year average is about 7 to 1, indicating that fewer than the normal number of young birds are in this fall's population.
Last spring's drumming counts were accurate, Larson said. Plenty of males, which do the drumming, were in the woods. Either something affected reproduction and brood survival, Larson said, or bird movements and weather patterns have made it difficult for hunters to find birds.
"A key part of this story, if in fact the harvest is down this fall, and even if we found out it had something to do with reproduction, is that we'll probably never know what happened to get us to this point," Larson said.
It's probably a combination of factors, not just one, he said.
Russ Sewell, regional biologist for the Ruffed Grouse Society in Minnesota, said several possible theories were discussed this week. Among them were these:
* Wet, windy weather during grouse season this fall may have changed birds' movements and made them more difficult to find.
* The effects of West Nile virus on ruffed grouse is not well-known but could be a factor.
* Inclement weather during nesting season last spring may have affected brood survival.
* Extended dry weather this past summer may have reduced the number of insects, which grouse chicks depend on early in their lives.
The group decided on no course of action other than to seek more information about West Nile virus, Sewell said.
If next spring's drumming counts show another increase, they will indicate that plenty of birds were around this fall, Larson said. Harvest figures for this fall, available next summer, also will tell part of the story, he said.