Do Birds' Feet Stick to Metal in Cold Weather?
Bird feet are covered in hard, non-porous scales. Birds do not have sweat glands in their skin so they do not produce moisture that would cause a bird to stick to a metal surface.
Birds have several other adaptations to help protect their feet in the cold. The blood vessels going to the feet (arteries) and coming from the feet (veins) are located very close together. This allows for heat to be exchanged so that the blood that reaches the feet is cool and the blood returning the body is warm, preventing the loss of valuable body heat. Birds can also reduce the diameter of the arteries, allowing less warm blood into their feet. With these two methods, birds can reduce heat loss in their feet by up to 90%!
Muscles need a lot of blood and can contribute greatly to heat loss. To get around this, the muscles that control a bird's feet are located deep in the warmer interior of a bird's body and all foot movement is controlled by the attached tendons, which need few blood vessels.
Birds that spend a lot of time in cold and snowy climates may have feathers down their legs and even on their feet, like Snowy Owls do. If temperatures are really cold, you may see a bird pull a foot up and tuck it into the warmth of its feathers. In extreme cold, a bird may even hunker down so that both feet are covered by its breast feathers.