2006-02-11 / Columnists

Mackinac Island Plants, Animals Adapt to Winter

By Patricia Martin

After a very mild January, winter has finally descended upon us. Temperatures have dropped to within the “normal” range with a couple of feet of snow on the ground. This doesn’t mean that the wildlife of our Island has totally disappeared. There are a variety of strategies that organisms use to survive the cold and the resulting dryness of winter.

Let’s look at plants first. The herbaceous plants (those without woody tissue) either die back to underground roots, stems, tubers and/or bulbs, or they’re annuals that only live for one season and die at the end. They leave behind many seeds, which will sprout into new plants in the spring. Many of the perennial herbaceous plants actually need a period of cold (vernalization) before they can produce new stems. Common examples of plants of this kind include tulips, trillium, and lady slippers. Woody plants either lose their leaves during the winter (deciduous) and concentrate their sap in their roots for the cold season, sprouting forth again in the spring, or they retain their leaves year-around (evergreens). These plants have sap, which is concentrated to lower its freezing point, and during the winter a slower rate of photosynthesis, which reduces the need for water. Many of the northern woody plants, just like the herbaceous ones, need the cold period so that their buds can open in the spring and they can produce new leaves and flowers.

Fish are cold-blooded organisms, which means that they take on the temperature of their surroundings. Many fish, like the largemouth bass, go dormant during the winter. Others, however, remain active. Yellow perch swim under the ice, feeding in schools, and are often sought by people who like to go ice fishing.

Reptiles and amphibians of our area generally survive the winter by going into true hibernation. Turtles, frogs, and salamanders usually dig deep into mud, slow down their metabolism, and go into suspended animation. Snakes often form a hibernaculum underground, often under a rotted stump. A number of snakes, often of different species, will curl up together in a ball a yard or more beneath the ground to spend the winter.

Birds and mammals are warm-blooded animals that cannot go into true hibernative states. Many birds, like many of our people, head south for the winter, not liking our cold north. It is interesting that some don’t move all that far. Take blue jays, for instance. We see them all year on the Island, yet studies have shown that those that we see in the summer are not the same birds that we see in the winter. Our summer jays head down to lower Michigan for the winter, while those that we see in the winter probably spent the summer in Canada. Some of the waterfowl do similar things. As long as the harbor isn’t completely covered with ice, some of the ducks and geese will hang around, but as soon as the ice forms, they head for the closest open water; often it means only going as far as the Cheboygan River.

Some birds are year-around residents of Mackinac. The small black-capped chickadee can be seen year-around flitting from tree to tree, scouring branches and shriveled leaves for insects or stopping by bird feeders.

Probably one of the loudest and colorful year-around birds on the Island is the pileated woodpecker. This large bird, with its bright red crest and black and white body, can be heard drumming away throughout the woods and town. Its favorite food is carpenter ants and it knocks away large holes in trees to get to them. Recently one of these birds has taken to pounding on the old sugar maple in front of the Parish Hall at Trinity Church. At the rate it’s going, we’ll be lucky if that tree is in one piece come spring. I’ve seen other new holes in trees throughout the Island and often see these woodpeckers flying. Insects are not the only food that these birds like. The other day I got a call from a friend who said he had seen several of them eating away on the fruit of the flowering crab behind the Fort. In addition to fruits and insects, they will eat nuts.

The largest and the most majestic year-around bird resident is the bald eagle. In many books they’re listed as migratory birds, only spending the summer in our areas, but around the edges of the Great Lakes they may spend the whole year as long as there is some open water. They need the open water, as they often eat water birds and fish near the surface. They also eat small mammals and carrion. A couple of years ago, I saw one working on a dead deer that had washed up on the shore. Just the other day, I saw a pair of mature bald eagles flying along the east side of the Island. It’s always a thrill to see them.

Mammals, like birds, are warm-blooded, but unlike birds they don’t have the option of flying south, so they have to figure out how to survive the cold. Rodents are some of the more common mammals on Mackinac. Some of them are active year-around. Meadow voles and a number of mice species are active under the snow during the winter, foraging for food, seeds, grasses, bark, and in the spring, we often see evidence of their winter runs in paths through lawns. Red squirrels are seen yeararound. If you ski in the woods, you often see piles of disintegrated pine, spruce, or cedar cones around the base of a tree, giving evidence to their activity. Red squirrels may nest either in a tree cavity or even underground in the winter. In the winter they often travel beneath the snow in tunnels. Usually the gray (or the black phase of the gray) squirrels are not seen as much as the red. During cold periods they often hole up in their tree nests until the weather is more comfortable, but they do have to hunt for food, either finding their stashes of food or locating new sources. This year, because of the mild temperatures, they’ve really been out and about. One rodent that really likes to sleep the winter away is the woodchuck. After eating like a pig to fatten itself up, in late fall it crawls into a den, which is between six to 10 feet below the surface of the ground. It then plugs up the entrance to keep the cold out, and curls up into a ball. During the winter the woodchuck’s metabolism is slowed down considerably.

Both the eastern cottontail and the snowshoe hare are active all winter, eating whatever vegetation they can find. The cottontail is more susceptible to predation during the winter because of its coloration than the hare, which is a good thing, because, frankly, they reproduce like rabbits. Most cottontails don’t survive to one year of age. Snowshoe hares are better adapted to winter weather, with their white winter coat and their large hind feet, which help them move on the snow.

The two species of wild canines that live on Mackinac are doing well this winter and are, of course, active yeararound. I’ve seen lots of red fox tracks this winter, though I’ve yet to see one. The coyotes, on the other hand, are a different story. There seems to be a number of young coyotes on the Island this winter, and I’ve seen them out at all times of the day. Usually coyotes are more active at dawn, dusk, or at night, but these young ones seem to be out whenever. They don’t seem to be much intimidated by people. The other day I was traveling along the main road near Mission Point, when I noticed a small coyote trotting along the road ahead of me. As I sped up behind him, he sped up. When I slowed down, he slowed down. When I stopped, he stopped and turned around as if to say, “Aren’t you coming?” This continued for about a mile and a half and then he just trotted off the road and let me pass. In addition to the shore road I’ve seen small coyotes on the East Bluff and on British Landing Road. These canines look pretty healthy and it’s no wonder, as they have plenty to eat. Most people think that these animals are scavengers and yes, they will eat a reasonably fresh carcass; however, they also eat rodents, rabbits and hares, muskrats, and other mammals, usually ones smaller than itself, though a pair of a family group may take down a sick or weak deer. They will also eat birds, snakes, frogs, fish, insects, and even fruits and vegetables. They really aren’t too particular, sort of like us in March, when our pantry cupboards get thin.

Keep an eye out for these and other winter residents of Mackinac.

Trish Martin is a yeararound resident of Mackinac Island, has earned a master’s degree in botany from Central Michigan University, and owns Bogan Lane Inn.

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