Counter current flow heat exchange.

How do ducks manage to stand on the ice and not melt it and fall through? How come they don`t stick to the ice?

Their feet are made up of bone, tendon and scales that are dead tissue with very few nerves in them. Because of this they don`t feel the cold as much as we do. But they do stand on it in one place for a long time. They manage this by having biological counter current flow heat exchange. It relies on a remarkable network of blood vessels called reat marabiley. Basically they cool the warm blood coming down from the heart and through the arteries by exchanging heat with cold blood that is coming back up from the feet. The cold blood is pre-warmed so it does not shock their system and their metabolism. The warm blood going to their feet is pre-cooled to pretty much ambient temperature. This is just above freezing  so therefore they don`t melt the ice. There is also no moisture to freeze and stick as birds feet do not sweet so they are dry.