It seems strange the talk of a reduction in the bee population, as I now have three nests in the house /garden.
I have had a nest high on an old chimney on our house roof which becomes recolonised every year (no idea what kind of bee. I love to see them arrive back - almost always 3 weeks before swifts return and colonise the eaves under the roof!
This year we also have a nest in a bird box on the side of the garage, the bees never bother us though we have to walk quite close by. There is also now another nest under a loose tile on the garage roof about 4 foot directly above the bird box. The bees seem to go in and out of both and from one to the other. Is it usual for bees to set up satellite nests like this close to the first nest?