Winter can be a difficult time of year for wildlife. Cold temperatures, deep snow, and an ever reducing supply of food impact the daily activities and survival ability for many wildlife. In general, wildlife have three strategies for surviving winter: migration, dormancy, or toughing-it-out. Many species of birds migrate to warmer climates in the fall and return in the spring. Migrations can be as little as a few hundred miles to many thousands of miles. Many species of small mammals and most species of reptiles and amphibians handle winter by going through a period of dormancy, which includes torpor and hibernation. These animals reduce their metabolism by lowering oxygen consumption rates and body temperatures. Most mammals and many birds, however, will stick around and tough the winter out.
Toughing out a winter hasn’t been so bad in recent years, but the arctic weather pattern we have experienced recently will certainly force some changes in how those who tough it out spend the day. There are a myriad of adaptions for toughing out a winter. A heavier coat of fur or downy feathers increases insulation. Fatty deposits accumulated within the body are metabolized during lean food periods. Daily movements are often reduced to conserve energy. Food preferences change based on what types of food are available. How wildlife digest food in winter can change. For example, the digestive enzymes in white-tailed deer change in order to cope with a change in diet during deep snow and severe cold as their diet shifts to more woody stems and buds. Many species look for shelter from the bitter cold and wind in thickets, dense shrubs, and briar patches. Other species use underground dens to escape the cold. Some species of rodents, like southern flying squirrels, will share a den with many individuals, huddling together to conserve body heat. Others may burrow in the snow, as snow provides an effective barrier to sub-zero temperatures.
There are many things you can do on your property or around your home to help wildlife tough out the winter. Plantings of both deciduous and coniferous shrubs and trees can supply areas to escape cold winds as well as provide a food source. Coniferous shrubs and trees that provide excellent thermal protection include eastern red cedar, eastern white pine, northern white cedar, eastern hemlock, balsam fir, white spruce, and American yew. When planting deciduous shrubs, select those whose twigs and branches overlap and lace together forming a dense canopy. Recommended deciduous shrubs for thermal cover include American plum, the shrub dogwoods (gray, silky, red-osier, and rough-leaved), hazelnut, and ninebark. Also consider planting sumacs (Rhus spp.), deciduous hollies (Ilex spp.), viburnums (Viburnum spp.), and coralberry. While these species do not provide much winter thermal cover, they do produce abundant fruits that persist through winter, making them important emergency food sources. Dense patches of blackberry and raspberry can provide excellent thermal and escape cover, especially when located near food and water sources. These shrub and tree species can be planted in groups around your property or used as ornamental plantings around your home and out buildings. Most of these tree and shrub species are available commercially through the state nursery, native plant nurseries, and some landscaping nurseries. Just make sure you are selecting species native to your area and stay away from invasive species!
Other habitat management practices that can increase winter habitat include cutting undesirable trees, constructing brushpiles, and planting food plots. Cutting undesirable trees and allowing grape and greenbrier vines to cover the branches can create good thermal cover, as can building brushpiles. Brushpiles should be no bigger than a small pickup truck. Heavier limbs and branches should be placed on the bottom with lighter branches stacked on top. Planting food plots and leaving a few unharvested rows of grain can provide food during extreme winter weather. When planning a food plot to serve as emergency winter food, I generally recommend milo, or sorghum. Milo is high in energy, can produce prolific seed heads with seeds that persist through winter, and the stalks and leaves provide good thermal cover in many cases. Be sure to include plantings of dense shrubs adjacent to food plots to serve as additional thermal and escape cover. Putting out extra bird feeders will be welcome by birds, especially when filled with oily seeds like sunflower and nyjer, or suet. Be sure to clear any deep snow from under the feeders to make seed more available and consider scattering seed on the ground near shrubs and other dense vegetation. Peanut butter and seed pine cones will be relished by many bird species and a fun activity for kids to make.
Let’s not forget about water. Open water can be just as difficult, or more difficult, to find during arctic cold snaps than food. If you have bird baths, try to keep ice free water available on a daily basis. If the air is so cold that bird bath water freezes quickly, then consider purchasing a few heated bird baths. My heated bird bath remained ice free, even during the -15 degree temperatures we just had. Sections of ponds can be kept relatively ice free by agitating the water. Special water agitators can be purchased, and water fountains will also work in some instances.
Winter bird feeding tips, Minnesota Department of Natural Resources (above photo provided by MDNR)
Everything Wildlife, Purdue University
Information on natural resources management, visit the Extension web page of Purdue University’s Department of Forestry and Natural Resources/Extension.
Rob Chapman, Extension Wildlife Specialist
Department of Forestry & Natural Resources, Purdue University