I got a call from a tree service about getting a hive they cut out of a tree (lowered down with a crane) and in talking to they guy he said they've cut 6 trees this year with hives and quoted at least that many more with hives where they didn't get the job. He said in the last two years he's found more beehives than he's found in the last 10 years combined? Given the numbers of swarms we've seen in our area I would take a guess that the bees are developing a resistance and are able to better survive without our help. Of course, on the flipside, there are also probably a lot of new beekeepers that aren't as good at keeping managed hives from swarming and are escaping and thriving for a short time. Hard to tell I guess.