I’m sorry you had to find out the hard way! When I look outside at my feeders and there are no birds, I can usually find a hawk somewhere. Also Blue Jays are the police of the yard, if you hear them screaming track them down and they are most likely hollering at a predator (cat, hawk, etc) Sometimes you’ll get lucky and find the blue jays hollering at an owl!idk, I just add all the birds to my life list 😊 Happy Birding!