I don't know if anyone can help, but my friend lives in a very old
house 1700s I think and he has discovered a colony of what presumably
may be masonry bees living in the mortar between the bricks on the one
side of the house. I haven''t actually seen the bees myself, only the
burrows but the mortar is quite literally 'honey combed'.
The concern is, would this weaken the structure of the wall? It surely
can't be helping? He cares about wildlife very much and doesn't want to
cause harm to the bees if he can help it but also wants to maintain and
protect the wall. Are there any bees that would burrow into such
material that might be rare or protected (he lives in the Cotswolds if
this helps). Is there any way he could repair the damage in the winter
and provide them with a new home?
Is there a way around this problem that fixes up the wall but doesn't
totally destroy this colony?

Any advice greatly received!!