Hawks, owls, (they both will steal a decoy topper), cows, house cats, a few dogs, raccoons, quite a few deer, horses, donkeys, llamas, people.
One piece of advice, if you are using an Ecaller and the herd of cows come running, mute the call and go get it before the cows get it. And in case you ever wonder, the bull is in charge in the pasture, you're just his guest.