do what i used 2 do to birds when i was a kid
bury a rat trap in loose soil and bait it with bread or somethin. when the birds peck the bread, it will either trigger and kill the bird or knock it in the head so that its disoriented and cant fly or will be KO'd.. rubberband its wings down and superglue the beaks shut, clip the wings so it cant fly, bread tie the feet together so it cant land or walk... or tie it to somethin heavy so that it cant fly off..
or post up by the feeeder with a ball bat, rig a taser to the feeder and shock them,