So you hear noises in your attic, okay you have squirrels, rats or mice. But after it’s been checked out there are no rodents in the attic, then its most likely bats. Bats don’t usually seek out attics of houses for roosting rather they get there for any number of reasons. First, if they are scared or startled, they may seek refuge in your attic, chimneys, and holes on your house. Some bats are so small that they can fit through openings as small as 2 cm diameter. Next, bats will seek nesting sites that are close to sources of food and water and because your attic is the right temperature and dry, it may be the perfect location. Bats will travel up to kilometer in search of a nesting location. If the noises created by bats are keeping you awake, there are many exclusion techniques found on google that are definitely do-it-yourself solutions, but first be advised that bats here in B.C. are a protected species. You will have to wait until the bats have left before closing off the entry points. It is also recommended that you be cautious around bats as they can carry rabies and that their feces can contain pathogens which can cause histoplasmosis.
gogreenpestcontrol.ca and exterminators Delta Ladner Tsawwassen Randy L. Bilesky BsF CPA RPF
https://www.delta-optimist.com/opinion/blogs/blog-a-little-batty-in-your-attic-1.23452814