Something attacked my onion seedlings

This sounds terrible. I wonder why they are picking on you? You will need to net or get a gun.

Once when the children were small, we had a crow that would perch in our apple tree next to the house and dive bomb into the windows every spring, starting earlier and earlier as mornings grew lighter creating a right racket. We ended up with black bin bags covering them so it couldn't see itself. It went on for about 5 springs. I borrowed a shot-gun off my wife's uncle but never was quick enough to ever use it.