How big a box for bumbles?

[Sutty]

I've noticed quite a few queen bumbles exploring my garden recently, presumably looking for nest sites.
How big a cavity do they need?
I've just enlarged the entrance to an old poly queen mating cage I won't be using, removed the frames & put a little bit of straw in the bottom.
Will that be big enough?

 

[jenkinsbrynmair]

birdbox size is usually OK for them

 

[Sutty]

Also, out of interest, as they have small honey stores do they ever get robbed by honeybees?

 

[user 819]

Also, out of interest, as they have small honey stores do they ever get robbed by honeybees?

I doubt it very much, disturb a nest and they will soon see you off.

 

[user 819]

Bird box as said is often more then ample in size or simply an old card board box quashed flat a little will suffice if it has a bit of cover from total damp from above.

I've noticed quite a few queen bumbles exploring my garden recently, presumably looking for nest sites.
How big a cavity do they need?
I've just enlarged the entrance to an old poly queen mating cage I won't be using, removed the frames & put a little bit of straw in the bottom.
Will that be big enough?

Yep equally should be ok , stick in a hedge or garden boarder out of the way and should used.

 

[Gilberdyke John]

I doubt it very much, disturb a nest and they will soon see you off.

I recall during a hive thermodynamics talk by Derek M at York BKA he passed the cryptic comment "Bumblebees can be grumpy buggers". He didn't expand but the message stuck.
There's a small, old hole in the concrete floor by the South West doorway to our stables. Evidently there must be an interesting cavity beneath and it seems to be occupied by bumbles a few times over the years. They never bother horses or humans so we leave them alone.