Walking outside between seasons, we can often see changes taking place. Flocks of birds weaving through the sky signal the fall migration. Milk weeds wither sending the next generation of plants floating on gossamer parachutes.
While many are quite obvious, there are also subtle changes that may escape our eyes. Like humans, many mammals put on new, warm winter coats. Yet unlike humans, who can toss on extra layers of clothing when we become chilled, wildlife has to survive on their natural coverings. Most mammals have two types of fur. One type of hair is called guard hair and the other called under fur. The under fur is the insulating fur. During the fall and winter, under fur grows in thicker and longer, adding an insulating layer like long johns. This under fur accents the roly-poly look of many animals during the winter. White-tailed deer grow the thick under fur. In addition their winter coat consists of hollow guard hairs. The hollow hairs help trap body heat.
Some birds will grow heavier down feathers during the winter months. Many songbirds can be seen on colder days looking like little tufts of feathers sitting on a branch. Fluffing out their feathers traps the warm air close to their bodies. Ruffed grouse grow fringes on their toes, which helps spread their weight and allows them to walk on top of the snow. Snow shoe hares and weasels change their brown summer coats to winter white to help camouflage their movements. One disadvantage to changing color can happen during a late snow year or early spring thaw. White winter coats are easily seen against the brown background.
Seasonal changes occur all around us. Some are obvious, other changes take time to stop and investigate. Take time during these transitions to watch for these changes.