Has anyone seen this before?
A friend sent me some pictures after checking her bee hotel of a ball of Osmia bicornis that appeared to be resting together and waiting out the cold weather. It was a sunny day so my friend removed the tray and put it in the sun and pretty soon the bees warmed up and flew off. However she noticed that as soon as she put the bee box back together the bees returned to the same spot and resumed their ball like behaviour.
Is this commonly recorded in O bicornis when the weather isnt 100% favourable?