we had same problem a few years ago and a game keeper told us about a ladder trap.they a trap ov 6 foot in lenth by 4 foot in width and 4 foot high put ladder in middle of top running centrel along top section cover rest ov trap with chicken wire or some thing like that and drop 2 or 3 eggs in the bottom guarenteed to catch the lot they fly in but can not fly out because wings to wide to get thru holes in ladder.good luck