I have had some requests for information on the construction of the bat roost we have on the front of our garage in Waukesha County. The fake door in the images has an outer covering of sheet aluminum, which just covers the roost itself. There is no entry into the garage. There are 3 chambers open top and bottom in the roost. Inside the 3 vertical chambers is about 8″ x 3/4″ x 54″ long. The outside of this roost is about 42″ x 54″. This roost hangs on the front of the garage. The inside of the roost there is no vinyl siding, it is all cedar. The bat roost was built on the ground and then hung up. This roost faces west and gets all afternoon sun. Bats come in and out from both ends, there is no rhyme or reason to where they are coming out next. I used rough sawn cedar boards for this, and the bats just cling to the face of these boards. They can leave the roost 2-3 or 4 at a time, just amazing. There are a few trees in the front yard. If you are standing on the driveway near the roost which happens once in awhile, the bats just come out and fly around you or over you. If you have parked cars on the driveway, they just come out and go over them, no collisions. The bats have been using this roost every year for probably 15-20 years. Numbers change every year. On the average in summer it has 25 bats in it during the day. When it really gets warm out, 70’s and 80’s it really fills up. When it gets extremely hot, they don’t hang out in the roost, it gets too hot. A typical evening at dusk the roost empties out. They usually empty the place out within 5-10 minutes. Bats are everywhere in the yard flying around catching insects probably mosquito’s. Bats seem to return to the roost at different times. If I am out very early in the morning I notice bats are returning to the roost. I only once found a bat on the ground under the roost, picked it up and let it rest awhile. After a few minutes I picked it up, held out my hand and it flew off. If a mess accumulates under the roost I just hose off the driveway right under the roost. I check the roost everyday and April 2 was the first of the year bats. When weather is cold, they may not leave the roost for a week or two.