I was out feeding my hens late this afternoon - it was almost dark out - and this bird flew onto a tree in my yard. I looked up at it because it was watching the girls intensly like it was going to attack. I was sure it was a hawk, but it looked skinny and it didnt have a fanned out tail like I normally see on them. It had a long skinny tail. The bird was greyish and brownish and whitish colors. The beak looked hooked but also not as severe as a hawk....but of the preditor type. So I'm guessing it really was a hawk, or a young hawk, or something else? I live in Southern California.