Here's the question. When the mercury drops to 30 below, and you weigh only a few ounces and live outside, how do you keep from becoming a bird-sicle?
Nature is amazing. Take our tiny, cheerful chickadees, who stay with us through the winter, no matter what the weather throws their way.
To keep from freezing solid, they grow more feathers. These feathers get fluffed up, trapping warm air next to the body. They can shiver to generate heat. They look for places out of the wind, deep in the evergreens, for their night-time perching. With no sweat glands on their legs, their feet don't freeze -- but you might see them pull first one leg, then the other, up into their warm feathers if it's getting too cold. Or, like this little chap, they can huddle down on top of those chilly little chickadee toes.
Since they can't store enough fuel for long, at night, chickadees go into a state of torpor, a deep sleep with drastically lowered body temperature, heart rate, and breathing. The result is a controlled hypothermia that can save a bird up to 20% of its energy. In fact, their body temperature drops by 10 to 12 degrees Celsius below the daytime body temperature.
Food is obviously critical -- the act of burning calories is what keeps the fire in these tiny birds' furnaces. To that end, they come to our feeders, one of our most frequent and favourite visitors. Chickadees carry away seeds, too, into caches. Memory is excellent -- up to at least 28 days after hiding the seeds, the birds will go directly there, no hesitation. Chickadees need about 10 kcal of energy per day to survive, so if you are going to put out birdfeeders, it's a good thing to be sure they are kept stocked up.
Mind, it's not just in winter that food is important -- the chickadee depletes much of its energy by feeding nestlings from six to 14 times an hour during the breeding season. February and March are the courtship months for these birds,who gather together in flocks during the winter, but separate into pairs for the warmer months.
They are a joy and a delight to have around, with their fearless bright eyes, and cheery call, taking on the winter, whatever it brings.
Sunday, January 23, 2011
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment