What does it mean when bees out of hive in a cloud?

[Jenxy]

Just had a call from my friend who started keeping this year, his bees are out of the hive in a cloud above the garden.... are they swarming? or is something else going on?

 

[hedgerow pete]

that sounds like a mating flight to me are they supercedding

 

[Heather]

Or swarming. Had a call last week - so still some around