Chances are that they are coming from your attic or somewhere under the eves on your roof. If you stand outside around dusk you will see the adults flying out.
When they are newborn they cling to their mothers when they go out to eat at night. As they get bigger and interfer with the mothers flying they are kept in a group nursery area. I suppose finding and putting them back in the nursery area is the best for them. But, bats have a history of being carriers of rabies.
It's your call as to what to do, but read about them online so you know the health risk involved.
I ended up with two babies inside of my house and I picked them up with gloves and put them on a pinetree next to where the bats fly out of my attic. They climbed up the tree. I don't know if the mothers were able to recover them or not, but I haven't seen them. Then I took the gloves off and burned them in a burn barrel.

I put these two under the front, open steps and they were gone at dusk. I hope they were safe. I'm glad we have bats as we have a tremendous amount of mosquitoes this year. I just don't really want them in the house. Maybe I'll get hubby to build us a couple of bat houses.

Unfortunately, it's been found that bats are not really effective in reducing mosquito populations (see the link). They're fun to have around, to watch them swooping through the sky at dusk, but don't forget the DEET!

--Johanna

Here is a link that might be useful: Bird and animal controls for mosquitos

I have bats and I do not know where they live. all I know is that when I try to sit outside at night they are flying all over the place and since I am scared of getting bit, I do not go out at night.

not to worry, they definitely don't want to bite you are even bump into you. They are VERY good flyers and may be near but will avoid you. they only bite in that rare circumstance when they are actually caught by someone and they are scared.
We have bats and night hawks that come down and swoop over our pool early evening. The night hawks actually scoop up drinks of water. I think the bats are getting bugs that are drawn to the water which is a good thing.

These were babies and we found where they were coming from. The ceiling pieces had moved out of place around the wood stove chimney. I think there's a nest in the hollow around the chimney. We put the ceiling pieces back in place and have just forgotten about it. They'll have to move on when it gets cold as it will be way too hot in there for them then.

Do bats migrate in colder climates or will they be there come winter?

They hibernate. Some bats hibernate where they are and some move to warmer climates to hibernate.

Generally, bats move to caves or tunnels to hibernate - they don't handle freezing too well, and deep enough caves or tunnels won't freeze. So unless your attic doesn't stay above freezing, they will move out for the winter. If it stays above freezing, but gets cold, then they will probably stay, but I think too high temperatures are as bad for them in winter as too cold - there's no food flying around in winter after all.

Look here

Here is a link that might be useful: Bats and Rabies - CDC

thanks for clearing that up dibbit. I guess I could have added more than one sentence. LOL