Nature Notes – Winter Survival


By Beth Dodd:


Are you ready for winter? Do you have good tires on the car and a cozy coat for the cold? Maybe you are packing your bags for Texas or Arizona. Or would you rather just avoid the whole season and take a nap until spring?

While you are busy preparing for winter, so are the wild things that live around us. Animals have three basic strategies for surviving the season. Some leave for better climates by migrating. Others stay put and hibernate or prepare to remain active during the cold season. Winter is the most difficult time of the year for wildlife. The season brings frigid temperatures and bone-chilling winds, snow and ice, and a scarcity of food and water.

Many of our local birds will say adios to Colorado by migrating south for the winter. The longest journey is made by Swainson’s hawks. After raising their chicks and eating mice, lizards, and insects all summer in Colorado, they head south, WAY south. Soaring in groups called “kettles”, they flock in growing numbers as they make their way down to Argentina. For individual birds who live at the northern end of their range in Alaska, this means a round trip of about 12,000 miles! Their migrations attract flocks of bird watchers who look for them at well-known migratory points in the southern U.S., Mexico, and Central America.

Another incredible migratory bird is the broad-tailed hummingbird. These tiny green dynamos zip to and from our feeders all summer. Their natural food sources of flower nectar and insects disappear in the winter, so they head south to western central Mexico. While this is an incredible distance for the tiny fliers to travel, the most amazing part is that they make the trip as individuals rather than in flocks. This means that the young birds which hatched in Colorado over the summer must find their way to their wintering areas and return to Colorado to breed the next year on their own.

While many birds depart for the season, other animals prepare to survive Colorado’s worst winter conditions. On top of Pikes Peak, the tough little pikas are going about their business on the alpine tundra. A ridiculously cute short-eared member of the rabbit family found only at high elevations, pikas store food all summer and fall, drying little haystacks in the sun and stashing them away. You can see them from the Pikes Peak Highway and hear their high-pitched calls. When winter comes, the pikas stay active in tunnels burrowed in the insulating blanket of snow, and munch on dried salad while waiting for spring.

Beavers also remain active all winter, cozy inside their thick, oiled fur coats and a thick layer of body fat. If the pond around their lodge freezes over, they can snack on stored food. During the fall, they cut green branches from nearby trees and submerge them for later use by poking the ends into the mud in the bottom of the pond.  

The big brown bat, a devotee of the all-insect diet, takes a middle road, staying in Colorado, but hibernating until insects emerge in the spring. When the weather turns colder, big brown bats look for a cozy spot like a hollow tree or small cave to spend the winter. During hibernation the bat’s circulation slows considerably and its oxygen use and heart rate are greatly reduced. The bat will draw energy from stored body fat, and may lose up to 25 percent of its weight by spring. If the bat did get enough to eat over the summer, it will probably die during the winter.

So whether you are planning to sip hot chocolate by the fire, zip down the ski slopes, or visit the in-laws in Arizona this winter, remember that outside your door wild creatures are spending the winter in their own unique ways and waiting for spring.