Tuesday, January 8, 2013

Chickadees in Winter

Black Capped Chickadee
Find four pennies and hold them in the palm of your hand.  They weigh about 10 grams (equal to 0.35 ounces or 0.022 pounds).  That is how much an average Black-capped Chickadee weighs. From the tip of its tail to its beak measures between 4.5 and 6 inches.  It has a wingspan from 6 to 8.5 inches. 

Unlike many other familiar birds, the Black-Capped Chickadee is a year round resident of Mid-Michigan.  How does a small bird like this survive winter in Michigan?

Chickadees have a higher body temperature than people.  They must eat a lot of a wide variety of foods to provide fuel for their body.  They choose to eat energy rich foods such as seeds, nuts, insects, insect eggs, and fat and bits of meat from dead animals.  Flocks of chickadees move around every few days to find new sources of food.  You can help chickadees and other birds by providing foods that have lots of fat and calories like sunflower seeds, peanuts, and suet. Chickadees are very bold and may even eat right out of your hand.

Sunflower seeds and peanuts help Black-Capped Chickadees  stay warm by providing lots of calories.

However, just eating a lot will not keep them warm by itself.  They need to keep their heat in and around their body.  Just as a person wanting to stay warm wears multiple layers of clothing to trap their body heat, a chickadee has multiple layers of feathers to do the same thing.  A layer of oily feathers blocks wind and water and a layer of fluffy down feathers provide insulation.  Chickadees can puff out their feathers to trap more warm air close to their bodies.  Just like people, chickadees will also shiver when they get cold.  Shivering helps to warm them up.

Sometimes, just like people, chickadees need to find shelter to stay warm.  They look for sheltered places like pine trees and hollow tree trunks to roost at night and during bad weather.  They will also use bird nesting boxes - so leave your bird houses up in winter.  Sometimes groups of chickadees and other small birds will huddle together at night to keep warm.  Chickadees can even enter a state called torpor in which they lower their body temperature and metabolism temporarily to conserve energy.

But don't their feet get cold?

Chickadee legs and feet are covered with scales that prevent heat from escaping too quickly.  Their feet are also kept at a lower temperature than the rest of their body so they don't lose to much heat.  If their feet do get cold, they will often pick them up one at a time and tuck them into the feathers close to their body to get them warm, much like a person would put their hand in a pocket for the same reason.

All of these behaviors and adaptations make the Black-capped Chickadee a true survivor of our northern winters.

For more information about Black-capped Chickadees visit the Cornell Lab of Ornithology Website.

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