By Kate Crowley
When Mike and I visited the Sax-Zim Bog last week we were not successful in finding any owls, but we did come across a pair of ruffed grouse sitting in a birch tree right next to the road. It was mid-afternoon and sunny, so the light hitting the tree and birds was golden, highlighting both their feathers and the reddish bark of the upper trunk. The birds seemed completely at ease with our presence. We didn’t get out of the car, but Mike stuck his camera with its long lens out the window and clicked away.
We knew that grouse eat the buds of aspen in the winter months, but we didn’t know they would do the same on birch. It was both entertaining and amazing to watch these medium bodied game birds, (they weigh between 1 and 1 ½ pounds), perching and walking along pencil thin branches that bent down under their weight. They occasionally opened their wings to help maintain their balance as they stretched their necks out to reach a bud, but for the most part they were like gymnasts on narrow balance beams, focused on their task and managing to stay upright.
I had been wondering what had become of the ruffed grouse who live in our woods, since I had not seen one all winter long. I know that when the snow gets deep, they will bury themselves during the coldest weather to use the snows insulating qualities to keep warm, but not once on my various outings on skis had one made itself known: Until this morning.
Mike and I went out early to enjoy the absolutely perfect conditions of fresh snow, blue sky and temperatures in the low teens. This was Mike’s first ski in several years and it was great to be able to go out together. He led the way, setting the track and I followed, enjoying the benefits of the compressed trail he created. Even when there are just a couple inches of new snow you end up walking more than skiing. Finally, at one trail juncture I offered to take the lead and do some of the work.
We had not gone more than 20 feet when there was a sudden explosion of sound and movement right next to my right ski pole. I squealed (yes I did) and watched a ruffed grouse go flapping up the trail. It’s probably a toss-up as to who had the greatest shock – me or the bird having a ski pole come down just inches away. Laughing at my reaction, I turned back to Mike hoping he had captured the moment on the Go-Pro camera he was wearing on his head, but sadly it was turned off. Still we were able to clearly see where the bird had gone into the deeper snow and where it exploded out. It was just a space of five inches or so between entry and exit. So, we at least know one grouse has survived this tough, cold winter in our woods.
In fact, this kind of winter with deep snow and deep cold may actually favor grouse survival, as compared to a winter with scant snow; the main reason being the ability to find shelter under the snow, which protects them from predators, especially goshawks. In a shallow snow winter the birds spend more time in the trees perched and looking for food and become much easier targets for a hunting hawk.
Ruffed grouse are a cyclical species, with numbers going up and down over a period of ten years. Here in the Great Lakes region, the low point generally tends to be mid-decade. Researchers have been trying to determine what causes this sort of cycle, but have found it difficult to pinpoint. There are indications that it may be tied in with the snowshoe hare cycle, in that a year with abundant hare means abundance for the predators that then produce more of their own offspring. With heavy predation the hare population drops and the predators must turn to another prey species, like the grouse.
A ruffed grouse in a best case scenario will be lucky to live to three years of age. In their first year fewer than half of the chicks will survive. Habitat is another big factor in their survival. As I mentioned at the beginning, aspen are their favorite food trees, but in order to protect its buds against tent caterpillars, aspens will sometimes produce a resinous coating on the buds which makes digestion difficult and the grouse must move to other, less nutritious food, like birch buds. They will also turn to apple, maple and ironwood buds if necessary.
If the grouse that we saw today makes it through the next month, there’s a very good chance that we will hear that wonderful, deep vibrational sound coming from the forest as he tells the world (and any female grouse within range) that he is done with winter and ready for a new cycle of life to begin.