If I may take the generalists point of view....

My policy on nestbox occupation is that nestboxes are for all
native wildlife in need of a nest cavity. Non-avian species
have also been affected by reductions in cavity space. If the
yellow jackets do not pose a threat passers by, I leave 'em.

If the mice are native (deer mice routinely show up in my
nestboxes), I leave 'em be.

Yellow jackets rarely stay in a box for more than a year. I've
also seen swallows evict wasps.



--
Mike Patterson
Astoria, OR
celata at pacifier.com

Reflections on an Ivory-billed Phoenix
http://www.surfbirds.com/blogs/mbalame/archives/002388.html