Trapper is right. I have been trapping some of the same areas for years. every year more come in. I think many of them are older beavers who were born in the area and moved away as juveniles. The good news is that it looks like you are down to just the smaller ones now b/c they are usually some of the later ones to catch b/c they don't seem to venture far from the den sites. Just stay after them. It is doubtful they will be gone and never to return but you can keep them in check. holler if you want help next year.