Think about it, they grasp the branches so they have to have muscles, that requires blood circulation, and those feet are real tiny compared to all the cold. Humans freeze with boots on. And deer, horses, cows, bison,elk,wolfs, they be standing out in the snow all day too.
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Posts: 4626 | Location: East Overshoe, second buckle from the top. | Registered: January 20, 2007
Birds’ legs and feet are covered with specialized scales that minimize heat loss. Birds can also control the temperature of their legs and feet separately from their bodies by constricting blood flow to their extremities, thereby reducing heat loss.
Birds will also perch on one foot holding the other close to their body switching feet occasionally and turn their head so their beak is close to their body to reduce heat loss. Birds that don't like the cold/loss of primary food in winter head south for the winter like our robins do.
I would bet a nickel, though, that there’s more to it than heat-retention strategies.
Birds don’t and cannot sit around huddled up all the time, even if they can do it during the coldest periods such as at night. The crows I feed walk around in the snow when the temperature is well below zero, and when my fingers would be all but useless after about 10 minutes if unprotected. There’s also no sign that their feet are warm enough to melt the snow, as my fingers do when I put them in a snowbank. They fly for long distances during very cold weather as well.
Birds’ feet are very small and thin, and it seems to me there must be some sort of antifreezing mechanism at work to keep them from freezing solid in a very short time when the temperature is –20°.
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Posts: 48382 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002
High metabolism. That's how they keep warm. THey have to eat so many multiples of their body weight every day. Just like I do.
"It did not really matter what we expected from life, but rather what life expected from us. We needed to stop asking about the meaning of life, and instead to think of ourselves as those who were being questioned by life – daily and hourly. Our answer must consist not in talk and meditation, but in right action and in right conduct. Life ultimately means taking the responsibility to find the right answer to its problems and to fulfill the tasks which it constantly sets for each individual." Viktor Frankl, Man's Search for Meaning, 1946.
Posts: 20769 | Location: The Free State of Arizona - Ditat Deus | Registered: March 24, 2011
Originally posted by roarindan:... they have to have muscles, that requires blood circulation,...
They have tendons that "over travel" their little toe knuckles around the branch (locking them when they "squat") and then they can relax a bit and stay clinging without undue exertion in wind, and while birdnapping.
So, less heat loss or chilling of blood if they had muscles in their feets.This message has been edited. Last edited by: sigmonkey,
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Posts: 45345 | Location: Box 1663 Santa Fe, New Mexico | Registered: December 20, 2008
Originally posted by jjkroll32: Countercurrent Heat Exchange. Very cool physiologic adaptation that many cold weather creatures have.
Another example is sled dogs' feet.
Just about to post this, but counter-current flow of blood shows up frequently it evolutionary adaptations - also in fish gills for extracting the maximum amount of oxygen from water.
Posts: 2186 | Location: NC | Registered: January 01, 2006
My favorite birds are Chickadees. Yooper Chickadees stay here all winter and are at my feeder everyday, no matter how cold. Their high metabolism requires lots of food to keep them from freezing. What everyone else has said about birdie feet is true. Highly adapted. If you are thinking about starting a bird feeder, feed to attract Chickadees. Friendly and tame, they will eat from your hands.
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Posts: 16947 | Location: Marquette MI | Registered: July 08, 2014
