When we first put our guinea pigs outside it was like we put a sign out for hawks. We have some in the trees near us but I hadn't ever seen them in/above my yard. We are at the top of a hill. The piggie cage is fully covered with a wood lid so they couldn't see the guinea pigs but could hear them. They'd circle and go below the fence (down the hill alittle) and then back up. Finally they'd sit on the fence. All the while, my dog would be laying inside watching and waiting... as soon as the hawk would land, he'd go running out barking like crazy. After about 2 days, the hawk stopped coming.
That said, my husband said he saw a hawk on our chimney when he came home today. Guess we better keep a close eye out.