Guilfordbeekeepers.org

Number 8 arrived at the bait hives around 2:40pm. I moved the oldest bait hive swarm into a medium super this afternoon, and set up another bait hive. I'm not sure, but I think it may have scouts looking it over. I had 3 bait hives sitting side by side. All collected swarms.

It sounds like you may have let several get away into the neighborhood in the last few years. Now their offspring are coming back.