Hangin' with Mr. Cooper's Hawk

I spotted an exciting silhouette atop the bird dome this morning:

Periodically, I see a hawk buzz the pigeons inside, making them flap frantically from one side of the cage to the other. This is the first time I had my camera ready.

I'm not really sure what the hawk is thinking as it circles the cage. Does it think that it could really catch a pigeon if it could just get at the creamy center of the bird-cage truffle? Here it is perching on top of the keepers' entrance. "Ahhhh, for the keyring.... and thumbs. Thumbs would be good."

"Or maybe somebody made a mistake and left a panel open?

"Better check all the welds just to be sure."

Maybe it's just attracted to looking at the pigeons? Here it is taking a human's eye view of them.

They don't like that very much.

But the pigeons really HAAAAATE it when the hawk goes all like:

"Pant, pant. Hunting caged pigeons is harder than I thought. They have some mighty defenses."

I used the "burst" mode on my camera for the first time. I only got one good shot that way, but it was a quite artsy one:

So the key in telling a Cooper's hawk from a sharp-shinned hawk is that the former has a rounded tail and the latter a square tail. Also, Cooper's is slightly bigger. Here is another example of a bird where I just don't have enough experience to compare the two well. This tail looks pretty round... right? But then it also looks slightly notched, which is a character of the sharp-shinned.
This bird was larger than a robin, about crow-sized, which would seem to place it in the Cooper's category. But then the female is larger than the male in most raptors, so if it's a lady sharp shinned, it could be as big as a male Coopers'. Making things still more difficult, this is an immature (=brown 'n streaky) bird. I'm sure the birders monitoring the raptor migration over in Marin could tell easily, but I'm an undecided amateur even with this pretty clear photo.

Anyway, hawks are cool. Happy migration, friend!