Squirrels are viscous little creatures. Did you know they eat nestlings? Here is a picture of one mowing on a dead woodpecker.
Oh and here is a picture of one of the little monsters eating a baby bird. I don't like to see anything suffer but squirrels deserve little sympathy - they aren't even native to the West. I was surprised when I heard they eat birds, local Audubon folks made a big deal out of it when it was found the squirrels were wiping out the birds in a local park.