Just checked my records - last year I’ve noted intense buzzing in alder patch around 14 April. Not sure if that was bumblebees or my herd or wasps (I keep wasp nests around for predation, they seem to get the deal and do not bother me). I’ve reduced insulation of the nest boxes to effectively nothing this year (there is even a large ventilation window covered with steel grate in the roof and just couple towels on top of frames to prevent full scale wind), so it’s much more calm now that last year, even though it’s warmer. Some success.
Just checked my records - last year I’ve noted intense buzzing in alder patch around 14 April. Not sure if that was bumblebees or my herd or wasps (I keep wasp nests around for predation, they seem to get the deal and do not bother me). I’ve reduced insulation of the nest boxes to effectively nothing this year (there is even a large ventilation window covered with steel grate in the roof and just couple towels on top of frames to prevent full scale wind), so it’s much more calm now that last year, even though it’s warmer. Some success.