Orientation flights and 'non-flying bees'

If you go to the apiary in the early afternoon on a lovely day in late May you'll often find the air filled with a swirling mass of bees.Try following the flight of an individual bee — not always easy — and you'll see she's flying in uneven, ever-widening, spirals as she gains altitude. You'll eventually lose sight of her amongst the hundreds of other bees doing the same thing.Beginners can, understandably, mistake these flights for swarming activity.However, swarming bees leave the hive in a mad rush and the swarm quickly assumes a 'shape'. The bees don't disperse, but instead become concentrated, eventually settling on a nearby branch or fence post, forming a cluster (the bivouac) around the queen.Orientation flights at a nuc entranceIn contrast, these spiralling bees do not rush out of the hive all at once, and they do not settle.They (briefly) disappear … off, up and away.The activity peaks and then declines.The exodus of bees from the hive tails off, and — although it's not…