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Hairy Woodpecker
Living in Canada, where our winters bring snowstorms and sub-zero temperatures, it only seems logical that birds would fly south to avoid these harsh conditions. But while some species migrate for the winter, others stay year-round, never leaving their home. These resident birds have developed special adaptations and tactics to survive the cold.
To endure our winters, birds need to solve two problems: maintaining body temperature and finding food, which is greatly reduced in winter. Feathers not only help birds fly, they also make superb insulation. Down forms a thick layer under the outer feathers, acting as a heat trap. Birds also retain heat by fluffing their feathers, thus expanding the insulation around their bodies. This fluffy barrier traps air close to their body, retaining up to 90% of their core heat. The secret to maintaining these layers of air lies in having clean, dry, and flexible feathers. This is why the cleaning and oiling process, known as preening, is so critical to keeping feathers warm and water resistant.
Chickadee
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Many winter birds travel in groups, using each other as a heat source. They often huddle together in shrubs, evergreen trees, and on branches to share their warmth. They form tight lines and jostle for position throughout the night, as those on the outermost edges lose more heat than those in the middle.
Cavity nesters, such as nuthatches, chickadees, and woodpeckers, may also seek shelter in tree holes, crevices, and nesting boxes at night to provide protection in poor weather. Woodland birds will move deeper into the interior to escape the cold winds.
Horned Lark
Large birds such as quails and ruffed grouse are known to burrow under fluffy snow, to insulate from the cold. However, smaller birds do not benefit from snow-burrowing. Although there is potential benefit from insulation, there is a potential cost. During sunny winter days, the top layer of snow melts, which then refreezes into a solid crust at night. Smaller birds may not be able to break through the icy crust the next day and could be trapped in the snow.听 听听
During the winter, birds truly live from day to day. When night falls and the temperature drops, they burn up most of their fat reserves and these reserves must be replenished the next day to survive the following night. This requires them eating a continuous supply of fatty and high protein food as fuel to keep warm. Sharp-billed birds dig into tree bark for various spiders and insects. Others switch their diets from fruit in the summer to winter seeds and nuts. Many birds also cache food during the warmer months, to ensure a supply of winter food.
Even with the extreme cold temperatures we have experienced this winter, our resident birds know how to maintain their body temperature and find food by adapting to their environment.
Brenda Gallagher听