This is a really interesting story to me. I have had many people offer me swarms in cinderblock and I always turn them down. I'm no handyman, and short of destroying the wall, there isn't much I can do to get at the bees. This was a great tale and pics. I am looking forward to the next update.
Here's the update. I don't know if I went into this before in this thread, but the first try at making a queen something went wrong (maybe she didn't return from the mating flight) and I had to give them another frame of eggs - which was successful and seems to have made a good queen.
Anyway, the trap out - I let them rob out the old hive for a few days until they lost interest in it. They didn't get very much honey, but I figured that if it was a small hive to begin with and after weeks of no stores coming in there probably just wasn't very much honey left to rob. It looked to me like the job was done - no bees going in or out of the old hive in the middle of a sunny day when the other hive was working hard. So, I came back after dark and took the hive home, and told the home owner that he needed to fill the block cavity with insulation, sand, mortar mix or something or sooner or later a swarm would probably move back in.
Mission accomplished - so it seemed. A few days later bees are going in and out of the block wall like nothing ever happened. I'm not even
trying to blame it on a swarm moving in - I'm pretty confident that I just didn't quite get the job done. By this time it was late August - too late to have another go at it.
The good news is that I get to try again in the spring - unless the weakened colony dies out over the winter which is entirely possible. We didn't have a nectar flow after the end of June so they are very likely to starve which will accomplish the exact same thing for the homeowner. If not, maybe I'll do better next spring with a little experience under my belt.
It's been interesting. And the little hive that I got out of it has built up like gangbusters since the queen started laying. I'm having to feed, and it's still a small hive - one cram packed 8 frame medium - but with a little luck and TLC it should be able to get through our (usually) mild winter.