Riverwoods Preservation Council

 Close window

Winter Trees
 Woodland Animals in the Winter

 January - February, 2006




(photograph courtesy of Ho Min Lim)

Animal species have two general approaches to winter: migration and adaptation. Birds migrate by flying south. Some mammals and fish migrate to warmer climates. Even insects migrate. Some butterflies and moths fly great distances. The Monarch butterfly spends the summer in the northern US and Canada and the winter in Mexico. Other insects, such as earthworms, termites and Japanese beetles, migrate by burrowing deeply into the soil to escape the frozen surface.

Many animals adapt to winter. Some grow thicker coats of fur to keep warm. Some, such as squirrels, mice and beavers, accumulate food in the fall to be eaten later. Others, such as rabbits and deer, continue to forage for leaves, twigs and bark to eat. And some, such as foxes, change diet from fruits and insects in the summer to rodents in the winter.

Animals adapt to winter by seeking shelter in places that can provide warmth, from an accumulation of leaves or a hole in a fallen tree to the attic of a house.

Some animals, such as skunks, woodchucks, raccoons, chipmunks and some squirrels, adapt to winter by reducing their need for food by slowing their metabolism through hibernation. In some cases, the animal’s heart rate can drop by 95% and their body temperature can be reduced by more than 50%. If the ambient temperature drops too low, the hibernating animal will begin shivering to generate heat. Skunks, raccoons and some chipmunks are relatively light hibernators, and awaken periodically to forage for food. Cold-blooded animals such as snakes, frogs and turtles, cannot generate heat to keep warm during the winter and become dormant. Many insects also spend the winter dormant.

Birds need food and water during the winter.
Many birds that winter in Riverwoods survive on the seeds produced in late fall by native grasses and wildflowers. A winter bird feeding station supplements the diminishing supply of seeds birds find in developed areas.

Place several bird feeders at different heights, to accommodate different species of birds.
Some birds, such as sparrows and pigeons, feed on the ground. Others, such as finches, chickadees and cardinals, prefer raised feeders. Some birds will flock to rigid feeders, while other smaller and more agile birds prefer free-hanging feeders that sway in the breeze. Of course, it is important to place bird feeders so access is difficult for squirrels, and away from windows that may be a collision hazard for birds.

Keep feeders clean and free of wet seed. It will spoil, and birds will avoid the feeder.

Not all seeds are attractive to all birds. Sunflower seed is favored by a wide variety of birds, such a cardinals, blue jays, goldfinches, woodpeckers, chickadees and nuthatches. Birds prefer sunflower seeds with a high oil content are preferred to the soft-shelled low-oil sunflower seeds people consume. Cardinals, chickadees and some woodpeckers also like safflower seeds. One advantage of safflower seed is that it does not appeal to squirrels. In general, it is best to avoid seed mixes, since they usually contain fillers that do not appeal to most birds and because not all seeds in the mix will appeal to all birds.

It is important to be consistent in feeding birds. Birds will circulate through an area, feeding at a variety of places including bird feeders. If you are inconsistent in keeping bird feed available in your feeder, birds will not become accustomed to it and will not visit it routinely.

Even more helpful than keeping a bird feeder full is planting seed-bearing plants on which birds will feed throughout the winter. Native flowers, such as coneflowers, will keep seedheads through the winter, attracting goldfinches. Some species of Viburnums bear large amounts of berries that will provide food for birds during the winter. Plants that do not provide food but that provide shelter, such as dense evergreens, are also valuable to birds during winter months.

Don’t forget water for birds. Ice and snow may not provide sufficient moisture for survival. Birds can’t rely on winter run-off from sidewalks and roads, since the water is usually heavily contaminated with salt. One approach is to put out a large container of water daily. Another is to employ a heated birdbath. Whatever approach you use, consistency is a key to attracting birds to your property.

Information on birds and other animals is available through the National Audubon Society, the Illinois Audubon Society, The Nature Conservancy of Illinois, the Lake County Forest Preserve District, and many public libraries and on the Web.

© Riverwoods Preservation Council- - Page last updated: December 2009