Wildlife biologist Keel Kemper of the Maine Department of Inland Fisheries & Wildlife takes a bite out of a key fall food source for woodland creatures -- wild apples. (Photo by Tanya Mitchell)
Migration, hibernation, adaptation
Wild creatures prepare
for winter in Maine
By Tanya Mitchell
MONTVILLE — All across Maine, people are scrambling to weatherize their houses, put snow tires on their cars and bring their warmest clothes down from the attic.
Outdoors, wildlife is also preparing for colder weather. As temperatures drop, wild creatures will adopt one of three strategies for survival — migration, hibernation or adaptation.
On a recent visit to the state-owned, 5,000-acre Frye Mountain Game Management Area, wildlife biologist Keel Kemper explained how Maine's creatures survive when the snow flies.
Migration
"The migration piece is most applicable to birds," said Kemper, who works for the Maine Department of Inland Fisheries and Wildlife. "I would suspect that probably in Maine there are 170 species of birds that migrate."
Maine's bald eagles may fly a relatively short distance -- from northern Maine to its coastal waters or from the coast to Massachusetts.
Eagles live largely on fish. "They go just far enough south so they can stay near open water and find some food," said Kemper.
Canada geese, which are known for their V-shaped flight pattern during the migration south, live on both vegetation and insects. They fly mostly to the southern portion of the country, but some populations living in milder climates like the Pacific Northwest stay put year round.
Kemper said northern orioles are one of Maine's 30 species of warbler, all of which are considered neo-tropical migratory birds. Because their diet consists mostly of insects, food needs can take these birds as far away as South America.
Robins, however, are a different breed. They are omnivores and can eat everything from insects and worms to fruits and berries.
"Robins are what we call short-distance, transitional migrants, and many of them might stick around for the winter," Kemper said.
For mammals, Maine's nine species of bat are taking to the night skies in small groups in an effort to follow their main food source, insects.
Just as some Maine creatures prefer to wait out the cold in warmer climates, birds from the far north see the state as a winter destination, like snowy and great grey owls.
Once promoted by natural resource agencies for its ability to provide winter food to birds, deer and other animals, autumn olive is now considered an invasive, non-native species. Though it can be found growing wild throughout Maine, additional plantings are strongly discouraged. (Photo by Tanya Mitchell)
Hibernation
While people often associate hibernation with bear, Kemper said the reality is more complicated. While Maine's black bear will seek out a winter den, which may consist of a small cave, hollow log or fallen tree, the animals don't sleep the entire winter away. Mother bear give birth to their cubs during the winter, and bear are known to wander out of their dens on exceptionally warm days.
But, Kemper said, bear still go the extra mile to prepare for a lengthy nap. Just before they head into the den, bears will eat sticks and other rough items from the woods, a contrast from the calorie-rich insects, clover, grasses and berries they gorge on in the fall to store fat. Kemper said the ingestion of sticks and twigs has an important role in the bear's ability to remain in their dens.
"They're making a plug so they don't have to go to the bathroom all winter," he said.
While bear do slow their metabolisms and heart rates down for the winter denning period, Kemper said they are considered intermittent hibernators because they "have the ability to fire everything back up."
Woodchucks, he said, are true hibernators. After fattening up on vegetation, which largely comes from grasses and vegetables from residential gardens, woodchucks dig holes and hunker down for winter. These animals can drop their heart rates from more than 100 beats a minute to four, and would appear dead if someone were to dig one up in the wintertime.
Wood frogs take winter napping to another level by hiding under leaf litter and allowing themselves to freeze. "Essentially their brains freeze, their eyeballs freeze and their lungs freeze," Kemper said.
The frogs return to an active condition once the snow melts — and after they thaw out, of course.
Adaptation
Deer seek out all the food they can in the fall, Kemper said. The menu might include leaves, apples, acorns, beechnuts, grasses and other vegetation. They are also shedding the brilliant reddish-brown summer coats for the grayish-brown winter fur. The winter hair is hollow, Kemper said, which traps air and keeps the animal warmer in cold weather.
As the snow deepens, deer seek out large stands of hemlock, cedar or spruce trees. Because of their social nature, small groups of the animals may be spotted in these deeryards. The environment provides deer with protection from the elements and from predators, as well as food. Deer will consume woody browse when other food sources are less plentiful.
"They're out of the wind and the snow is caught up in the trees, so the snow depths in those areas are reduced," Kemper said. "That allows for minimum expenditure of energy."
Moose, said Kemper, are made for tough Maine winters.
"They have these giant, long legs for walking in the deep snow, and these huge bodies," said Kemper. Their size alone helps these mammals to stay warm.
Like deer, moose are social animals and tend to move in small groups. Kemper said moose will also fatten up in the fall to prepare for fewer food sources. Moose have a similar diet to deer, Kemper said, although when it comes to woody browse and twiggy foods, moose can digest much larger helpings than deer.
The ruffed grouse is another of Maine's adaptors. This ground-dwelling bird typically lives in old fields or orchards, and eats leaves, fruit, and some insects. Come the tough winter months, though, these birds take to the trees to feed on catkins of poplar trees, the fruit of wild apples or the seed heads of staghorn sumac.
Ruffed grouse also use snow for insulation during the frigid nights.
"When they want to go to sleep, they fly at full speed into the side of a snow bank," said Kemper, creating a warm and well-insulated snow cave around themselves. In the morning, the birds break out of their caves and take off again. If there is a cold snap or heavy snowfall, the ruffed grouse might remain in a snow cave for a few days.
The state bird, the chickadee, eats everything from the catkins of poplar trees and seeds on the forest floor to the food found in residential bird feeders. The small birds are also known to eat snow fleas, mites or spiders that may be hiding in tree bark.
Chickadees must eat constantly. "They shiver all winter long to generate heat," Kemper said, which burns calories rapidly.
Kemper said the chickadee can also bring its body temperature and metabolism way down to conserve energy, a state known as torpor.
Many Maine people can be found in the same condition on mid-winter weekends, half-asleep on the couch, preferably in a shaft of sunlight.