A few days ago a friend took a swarm.(Yes, I know...it is very late) The swarm was put into a top bar hive. Next morning they were all clustered on the outside of the hive. They were put back inside and this morning they, again, clustered on the outside...then they took off for parts unknown. I, too, have encountered swarms not accepting a top bar hive. While hiving swarms into a Langstroth hive, I have never had a swarm leave. After some thought, I wondered if the act of marching into the hive might have something to do with the bee's accepting their new home. All my top bar hive installations have been by pouring the bees in the top...then installing the top bars. With Langs, however, I always spread a small sheet in front of the hive and pour the bee's in front and have them walk in on their own. Perhaps having the bee's walk in on their own does something to signal to them that swarming is over and it is time to set up housekeeping. Maybe being unceremoniously dumped into the tbh does not create a situation to signal that swarming time is over...so they stay in swarm mode. Has anyone else made similar observations or formulated theories concerning the acceptance or rejection of top bar hives versus Lang's?