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Wednesday, 18 October 2006 00:00

Tisn’t the season, but...

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A couple of Sundays ago Bob Olthoff, Blair Ogburn (senior naturalist at Balsam Mountain Preserve) and I were at Balsam Mountain searching through a mixed flock of migrants, looking for any newcomers when we heard someone kickstart a motorcycle in the woods behind us.

 

Well, it wasn’t really a motorcycle. We just kinda turned and looked at each other and murmured, “grouse.”

Now a grouse drumming at Balsam Mountain or anywhere else in the Southern Appalachians in April or early May wouldn’t be uncommon, but it was October. Then, perhaps to reassure us, the grouse drummed again and then again. The drumming loosened one of those memory screws, and I recalled that Bob and I had seen a group of male ruffed grouse displaying at Balsam Mountain last fall.

It’s not uncommon, in early autumn when temperatures are still warm, to see spring-blooming plants like violets flowering. It also occurs with cultivars like forsythia. The flowering of many plants is known to be associated with photoperiodism — the amount of daylight and darkness experienced each day.

Scientists have also linked photoperiodism with reproductive cycles of some mammals and birds. Studies with hamsters have shown that maturation of the testes is controlled by day length. Research with dark-eyed juncos and white-throated sparrows have provided similar results, i.e., day length appears to influence the development of reproductive organs.

A study in the Journal of Biological Rhythms also links photoperiodism to egg production in some gallinaceous birds. Gallinaceous means “chicken-like” and refers to birds from the order Galliformes, which includes grouse, quail, pheasant, wild turkey and others.

I ran across another Web site, Hinterland Who’s Who, that noted, “In autumn, when the young are almost fully grown, there is another period of relatively intense activity. Males begin to drum again, and young grouse disperse throughout the forest, seeking a place of their own to live. Some may establish themselves on the territories of old birds that have died.” But this Web site didn’t delve into any physiological phenomenon associated with the behavior.

Photoperiodism is also cited as one of the stimuli that trigger migration. I suspect it plays some part in the fall displays of the ruffed grouse. Does it signal time for some type of seasonal movement — the dispersal of this year’s fledglings — that coincides with migration in other species? Grouse are non-migratory. That seems plausible with the more mature, dominant males drumming and displaying as if saying to the youngsters, “Don’t even think about moving in here.”

Or maybe it’s some kind of reproductive twinge massaged by day length that just makes the male grouse randy again for a few days in autumn. I imagine it’s all tied together somehow — biology is never as neat as we would like it — and that photoperiodism plays a part.

Whatever it is, the Tom turkeys are also feeling their oats. The week after the grouse-drumming episode I saw three Toms out in a recently hydro seeded area enjoying their ready-made buffet. At least one was enjoying it. One was getting no enjoyment because the third gobbler was constantly circling him, fanning his tail and sticking his neck out — likely a display of dominance.

I don’t know what it is that gets into these males this time of year, but I’ve got to go now and order some flowers for my wife.

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