The first is a pretty common sight. On two occasions I’ve observed crows repeatedly swooping up and throwing a nut to the ground.
In Vancouver’s Confederation Park, I sat by a little puddle. Presently, a crow flew in with what appeared to be a large hunk of dry bread in its beak. It proceeded to throw the bread into the puddle. Then it pecked at it until it broke up. Then it ate the pieces. To me it was evident that it had deliberately put the bread and water together to prepare its cuisine.
In Port Coquitlam, around 1997, a hawk flew over my head, closely pursued by two crows. I thought that was pretty funny in itself, but a few minutes later I saw (what had to be) the same two crows flying back, one of them with a beakfull of grey feathers.
I wonder what that crow meant to do with those feathers (surely it could have spat them out). Maybe it meant to decorate its den.
In Renton, WA, around 2000, my friend Corey and I saw a bald eagle being pursued by about a hundred crows. Probably the crows couldn’t do much physical harm to the eagle, but it certainly wasn’t doing any hunting.
In Potsdam, I watched Hooded crows apply various strategies to open nuts (usually hazelnuts). The most common was to swoop high and drop the nut repeatedly on a hard surface. But I also saw them placing a nut on the road, and then perching nearby. (This is risky: if another crow sees your nut, it’s gone.) And I watched one uncertainly placing a nut on a tram rail. My impression was that it wasn’t quite sure what it was doing— it never got the nut to stay on the rail, and waited while the nut was just near the rail. Could it be, it had seen another crow successfully execute this manipulation of human technology, and wasn’t quite sure how it was done?
I have observed an effective means of opening hazelnuts on soft ground, employed by the Saatkrähen. They make a small hole in the ground, put the hazelnut in it, then whack the nut until it opens. The nut is held in place by the hole.