A few years ago, on a bright sunny fall afternoon, we were hiking along a quiet trail in the west country. Suddenly, we detected some movement up on a small side hill. Lifting the binoculars for a closer look, I made out the form of a ruffed grouse, strolling slowly in our direction. I was amazed at how remarkably camouflaged it was against the vegetation, especially when it stopped. Luckily, it continued in our direction, so I was able to get some photographs and marvel at how closely it matched its surroundings.
Each November, I make a pilgrimage to Kananaskis Country to look for white-tailed ptarmigan. These species — unlike their ruffed grouse cousins, which remain cryptically coloured all year-round — molt each fall into pure white plumage. Thus attired, they become “one” with the high-country snowpack. When tucked up against a tree, only the most careful observers can detect the tiny beak and coal black eyes that reveal their presence. As the snow melts in the spring, these brilliant white birds slowly transform back into drab browns and grays, colours that make them equally difficult to detect in their mountainous summer homes.
Snowy owls remain white all year-round. They nest in the Arctic, where the brief nesting season doesn’t warrant a plumage change. And when they come south for the winter, they are already suitably attired for our snowy landscape. While they blend in well when sitting in a snow-covered field, their habit of perching atop power poles and signposts makes them highly visible. With few predators to worry about, they aren’t so concerned about being camouflaged.
Snowshoe hares are the classic example of a species that changes colour with the seasons in order to maximize the benefits of camouflage. Unlike feathers, which can be molted out quite quickly, it can take weeks for fur to change colour. If the winter snow arrival or melt doesn’t coincide with their molt schedule, individuals stand out against like beacons against the “wrong” background. In these cases, the adaptation to molt comes with increased risk.
Myrna Pearman is a retired biologist, nature writer, photographer and author of several books. Her books are available at www.myrnapearman.com. She can be reached at firstname.lastname@example.org.