Since this is winter people will have a lot of problems with squirrels bats and
mice of course and as Pointed out in the exclusion in the mouse section of this blog how to block any holes in the foundation around pipes voids openings near the roof line for bats in a pinch for a quick fix steel wool but I would get some copper mesh as soon as you can its called (stuff it ) and I used it on all my jobs while doing mice and wildlife work for big company
its hard to find you can get it here wildlife life control supply   it does not rust lasts forever and stays put just push it in the hole jam it in tight can be used on bats mice . And another reason for the link its the place for any wildlife problem  moles or any wildlife problem that goes behond home pests talk to them and Im sure they will get you what you need handy to have .