Hey everyone, at first sight this is exactly what I thought was happening, generally when you have many bees gathering in an area not their hives they are either foraging, moving or drinking, in this case they were hydrating.
It has been very hot of late and bees need water to regulate their hive temps, bees are very resourceful and ingenious in finding food and water in both their near and far surrounds.
Trust you have an amazing Sunday.
Cheer$;)