bee protest?

When I went to feed Ben this morning I found a swarm of bees in his trough.  That has never happened.  Pretty sure these guys were just passing by and dropped in for a drink and a swim (or perhaps to see what all the internet fuss was about) and not part of my local hive.  They were all gone by the time I had drained it down half way.  Decided it was the perfect excuse to clean out his big bowl.  Ben was quite curious about it once I tipped it up to dry out this evening.  He will be on his little bowl for a couple of days.  90,92,68,0,B