This winter challenges man and beast with wind chills reaching minus 45 degrees and snow over 4 feet deep. When annoying weather beyond our control makes life a bit testy, one good diversion is to watch the birds survive the rough winter weather. It is easy to forget our own problems when watching what our little feathered friends go through just to stay alive. And we think we have it rough!
the drama of survival unfolds at the bird feeders. How do they do it? How does something as tiny and fragile as a sparrow adapt itself to survive cold weather? Either by creation or design, birds are up to the challenge.
A little research goes a long way. For starters, a visible downy coat gives the first clue to bird survival. Eddie Bowers offers nothing like it. Semi-plume feathers provide insulation trapping air next to the body. On cold mornings birds appear “fluffed-up.” By fluffing their feathers birds create air pockets providing necessary insulation. And, by crouching down and puffing out the feathers on the belly a bird can warm its feet. Exposed parts like the beak and eyes may be tucked beneath a wing for protection. Their body oil is spread on feathers by preening and repels water as well as enhances the insulating effect.
A bird’s feet receive special attention. While human feet might be the first thing to get cold, bird feet are specifically designed to protect against heat loss. First, a specialized covering of thick scaly skin retains heat. Second, birds are able to control the temperature of their feet separate from their body temperature. Beneath the specialized skin is a network of fine arteries and veins. The arteries carrying warm blood are positioned very close to the veins. The warm blood from the arteries warms the cold blood in the veins before it is carried back to the body core and ultimately the heart. This unique system provides warmth to the feet.
A phenomenon known as thermongenesis helps birds defeat the cold. Just like humans, birds generate heat through an involuntary muscle contraction we call shivering.
And then there is the phenomenon known as deep sleep. Birds experience a drop in body temperature in the evening. This state of torpor, or reduced metabolism, helps conserve energy. Torpor reverses itself with daylight.
As long as birds can stoke their furnaces with energy-producing food and stay out of the wind, they are well on their way to survival. Birds consume a diet high in fat and in doing so they store energy for eventual consumption during the night. Some birds have pouches in their throat. During the day birds such as the Common Redpoll fill their pouches with seed to eat at a later time.
Birds also find warmth from each other by huddling (cuddling?). In this way they share their body heat. Typically, birds will find sheltered roosting spots in woods and bushes.
It is never too late to start a bird feeding program. Wintering birds such as sparrows will be especially grateful and will repay you in spades -- or more birds.
What better way to help our feathered friends than with food? Different seed attracts different birds. Finches and redpolls like their thistle seed. Nuthatches and chickadees like their sunflower seeds and suet. Most satisfactory for many birds is an all-purpose mix of sunflower seed, safflower, millet, peanuts and cracked corn which should attract the broadest variety of birds.
A value-added feature of feeding birds is that birds busy eating at a feeder will attract other hungry birds. The avian welfare system knows no bounds. Year-round feeding ensures a steady stream of visitors especially during the spring and autumn migrations.
What’s in your bird feeder?