How do you evict bats that have moved into your attic vents ?

Call the county ag agent at your county seat for advice. I would suggest that if there is any issue at all with rabies in your area, call a professional to have them removed. It's important for DYIers to know when to get help. Depending on what your Agriculture Agent tells you, this is likely one of those times. You can, however, make it uncomfortable for them to come back. The ag agent can help you know and understand that, as well.

If they're going to be around for awhile, or to prevent future bats, invest in one of those sonic plug in pest control devices. I hear they're not expensive, and they do work for mice, rats. Read the package to see if they'll help get rid of the bats. Question? If there is a screened area, how are they getting in? May want to reinforce it.

Try throwing campher flakes into the attic. Worked to rid us of squirrels!

Here see if this link helps - think you might need to put up additional screen material - and somehow come up with a way to have it look attractive. Good luck.

http://www.atticpestauthority.com/bats-in-attic/

If I read right, they are in the vent and not the attic. The inside screens are keeping them out but they hang onto the vent. I would wait till dark when they are gone and use some steel screen hardware cloth and install it on the outside of the vents.

http://www.acehardware.com/product/index.jsp?productId=1290445&cp=2568443.2568451.2624969.1302712

Thanks, the outside screen was my next plan of attack. I am having screens made that match the house screens but they will still look added on since there is no good way to attach them.

Naomi , thank you, great article that sums up all I have read. I have been told that the professionals in our area have starting charges that are estimated at $1500. So I am trying it myself, I have a date of September 30 As a goal . I visited the local big box home stores and a sonic device was recommended, he said try it for two weeks and return it if it didn't work. I would have kept it for future infestations... it just did not work. They do have a sonic one online specifically for bats at double the price that I may try, but the spider/mouse one from the store doesn't work. I have dealt successfully with, chipmunks, raccoons, possums, deer, skunks, bees and wasps, even woodpeckers and swallows bothering the house since we have been here but these guys are tough. If I get something that a homeowner can use that works I will post it here. I want to get them back into the woods out back Of the house. I have even been looking at bat houses to put in the woods.

Try placing an AM radio in the attic that is set between stations with all those high pitch annoying sounds. For best results this will need to be done at least an hour before it starts getting daylight. Maybe use a programmable timer to turn it on and then off after sunup. Keep disturbing the bats anyway you can....noise, water, poking, they will move.