It happens to me to. I catch swarms here on my farm. Plug them up at night,then move them hundreds of yards to another area and it never fails that some of the bees find there way back to the tree. I'm sure someone with more experience than me will have a better option for you. but here's a couple of things I have done. After they are there for a day or 2 I will place another swarm trap in that same location. The bees WILL go inside. Then I plug them up after dark, the next morning I will take them down to where the rest of there colony is and open the box with the entrance facing the hive that there colony is in. Usually mid day. In my experience they start nasonoving and move in with there folks. It might not get all of them. But will drastically reduced the numbers hanging out on the tree. The other thing I have done is just left a frame of comb where the bees are and at night they'll be on it. Makes it a little easier to move them. I also found that after a day or 2, the ones on the tree are pretty pissy.
