Crows have long been recognized for their intelligence. Lately,
the crow's ability to make and to use tools has been acquiring
this bird a great deal of attention and scientific study. In
this video you'll see a crow pick up the lid to a jar, set it
down on the apex of a snow-mottled roof and slide down one side,
carefully keeping its feet on the lid until it gets to the
bottom. Then it picks up the lid, flies back to the apex, tests
out another face of the roof, finds it lacking, returns to the
original position, and slides down again. More about this video
at The Atlantic.