Killer Bees?

That was kind of spooky just now - I was sitting outside on the terrace, peacefully reading my newspaper and working on my tan when, all of a sudden, a menacingly low, humming buzz started out of nowhere. And then I saw it - a huge bee colony was swarming just a few metres above my head in the air and slowly moved towards the little burn in the neighbourhood. Fortunately, that wasn't too close an encounter of the first kind.