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from Friday Morning, January 28

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I know the reason, but I still can’t quit figure out why the feet of tiny birds do not freeze on a cold wintry day and why they can go barefoot in winter.

From the Internet: There’s a very good reason why even the coldest of winters aren’t much of a problem for most birds: Their feet are ingeniously designed so that they’re already cold to begin with. Thanks to a network of arteries — called rete mirabile or “wonderful net” — a bird’s heart is wired to its feet in such a way that by the time the tiny amount of blood gets down there, it’s cooled. And when blood flows back up, it’s warm. This heat exchange system ensures warm blood stays close to the bird’s heart, while the cool stuff dribbles down to its toes. The bird feels very little down there, and, most importantly, doesn’t experience any heat loss.