I hived one of my own swarms Wednesday ( 3 days ago). They have been in a deep since that time and I fed syrup over the inner cover. Today I went out and put on a new jar of syrup and some pollen sub patty. I then commenced to cutting the grass. After the second time around the feild with the lawnmower, I noticed this same swarm was leaving the hive and I watched as they settled on the same limb as before but only about 6 foot higher this time. I stood there thinking of a way to get to them and then went back to the house to get the tractor and ladder and other stuff I would need. I went back out in about 10-15 minutes and the bees had gone back into the hive again! The only thing I can think of is that the lawnmower put out some vibrations that the bees did not like. I was glad they came home as that was a big swarm and I took several stings around my ankles when I caught them the first time.( forgot my duct tape) Has anyone ever seen anything similar to this happen?