I play golf at a club just north of the city. When I noticed that you never see squirrils early in the morning and late in the afternoon, I asked a woman in the Audubon society about it. She said that squirrils can't look up, because their eyes are on the side of their head. They look side to side. So the way they know the hawk is around is by the shadow. But they can only see his shadow when the sun is realitively high in the sky. As the sun gets lower, the sun moves farther and farther away, and the squirrils know it's time to call it a day.
Very interesting about the squirrels.
That is fascinating. I have a squirrel family and I can set my clock by when they are out amazing.