Last summer I discovered that we had bats living in our house -- my first thought was in our attic. I also figured it was just a couple.
Since then I"ve done a fair bit of reading and discovered that bats have several roosts. I've also discovered that they sleep about 20 hours or so a day -- they fly for an hour or so at twilight and again at dawn.
The other night at around 9 pm I sat down with a large mug of coffee and binoculars and watched the bats leave. I think I've discovered that they are not actually in our house -- they roost in the eaves. I've also discovered that there are a lot more than I figured lol..I counted 25 leaving the house in about 30 minutes....and I've read that only a fraction of the colony leave on any given night....
When we moved into the house, 10 years ago, that first summer we had a bat in the house...I was able to safely remove it...none since....
Even though I only discovered the bats leaving from our house last summer, I have a suspicion they have always been here. First, I would see bats flying around our home -- we are in a rural area...nearest homes are 800 and 1000 m away so more likely source if roosting in a home is ours...and the place of departure is front of the house....I am rarely ever in front of our house at 9 pm (this is where the bats are exiting from)....it was purely chance that I discovered the bats leaving from under the eaves in front of house...I did see a lone bat a few years ago departing from vent over garage...and I have found bat droppings in my workshop (which is about 100 m from my house) -- at the time I thought the droppings were from the nest of very neat mice who wouldn't eat the bait I set for them...
Anyway...my thought is....should I really worry about getting rid of the bats ? I know there are issues with the guano and that bats carry many diseases in addition to rabies....but if I hadn't discovered the roost by accident, I probably would never have known about them...my heightened awareness may be why I see more bats around then ever before.