Some good advice was given to the original poster.
I’d add that if you are hoping to either exclude the bats yourself or live with the occasional bat showing up.
Keep a few things in mind in relation to your initial post.
1) the bat is going to see you as a predator. In their world you are plenty big enough to kill and eat them. Not all bats vocalize but it’s really depends on the chase, capture, moment it happens etc and species. Some species go off like a car alarm even if being held very softly in a fleece or other material.
Often this vocalizing and biting is stated as “aggressive” when in reality again they are prey animals for everything from snakes, owls, raccoon, cats, hawks, etc...
Anyone who has ever grabbed a “helpless” little squirrel can affirm when something thinks it’s about to be eaten, they’ll do what they can to stop that.
To that end, always use a barrier. Container mentioned above is a good one or shoe box without big holes in it.
2) be careful if you decide to try to remedy the home to keep them out.
Too many folks go outside and try to fix the house, often waiting till they see some fly out and when no more come they seal the hole and find there are still bats present who are now left with only your interior to go into as they can’t go out.
We tell folks who want to DIY to please stay inside your home, look for the holes and gaps and crevices like you are winterizing for hot air loss. Do not go outside without reading some guidance documents about exclusion.
Proven management practices involve finding entry points, adding proper one ways to allow the bats to exit, giving the bats 10-14 days to exit of decent weather before removing vents and sealing.
But that’s the simple post version.
It can go wrong and be worse than if you did nothing.
This year I’ve had folks within 20 min of leaving a voicemail get on a ladder and start blowing foam into holes during the day. This of course ends poorly for both bat and human.
When done right, good for bats and humans.
When done wrong, bad for both usually.
There are lots of guidance documents from state extension, BCI has a good page on exclusion and federal agencies have an updated acceptable management practices as well on the white nose syndrome website under resources tab.
Any of those will get you further down the road positively than not.
But if you have a serious issue with a fairly decent colony and can hire it out, check the list LA posted.