Bat roost construction information in Waukesha Wisconsin on April 3, 2017

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.

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Bat leaving the roost at dusk…

1 chamber looking up inside the roost

1 chamber looking up inside the roost. You can see light at the top where it is open. It appears here I also used a piece of rough sawn cedar plywood.

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2 of the 3 chambers looking up

A bat leaving...

A bat leaving…

Another view of a chamber

The bat, a dark spot area about 1/3 of the way up inside on the right side out of focus. Another view of a chamber looking up. Image taken 4-3-2017

Bat coming out...

Bat coming out, this image taken in 2011…

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Window to Wildlife features the photography of Jim Edlhuber. A lifelong native of Wisconsin, Jim has been photographing wildlife for 20 years. He considers himself an avid photographer and is always trying to capture nature and wildlife through his lens. He is in several photography clubs and has won numerous awards for his work. In recent years, Jim has focused mostly on birding photography and finds it to be the most challenging.

3 Responses to Bat roost construction information in Waukesha Wisconsin on April 3, 2017

  1. Jennifer Holter says:

    This is very interesting. I like the way it looks like it just part of the garage. Do you have Nighthawks, and is there a competition for the mosquitos?
    Have you had neighbors object?

  2. Laura L. says:

    Cool idea and I like how you got so many photos of the bats in and around there.

  3. Gerald Haiar says:

    This is the most successful bat roost I know of.Neighbor family put one up on our property line. Fine with us, not fine with the bats, none seen in three years. Makes me feel bad as it was a scout project for their son.

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