Bat House Forum

[IowaNate]

My nieghbor's house has been refuge to atleast 8 hibernating big brown bats for several years. He likes bats, but they occasionally make it into his living space. This Fall he has decided to block up the entry points with me doing a safe exclusion...where will these bats go?
I took the liberty and did something extreme (which may or may not work). I live in a 1-1/2 story house with attic crawl space, so I dedicated one stud cavity (14.5" wide and 48" tall) to the bats. I made a 1.5" tall by 6" wide hole into my house then mounted a sigle chamber bat house over it with a matching hole in the back. I pet screened the interior of the stud space and even added a few baffles. Then I pet screened over the stud space, thus eliminating any bats from getting into my living quarters (and making it possible to view any occupants). I currently have a remote digital thermometer with the sensor in the stud space.
My goal is to keep the temperature between 35 to 40 degrees as much as possible during the Winter months. I have tried to find data on ideal humidity levels for big browns (I know they can tolerate much lower humidity than little browns) but haven't come up with anything.

It's a drastic experiment, but one that I was willing to try to keep a safe home for these bats.

[cloudman75]

Nate,
I have been on the computer for several hours the last couple of days and understand you not finding a specific humidity requirement for
big brown bats. I did read that they could tolerate a body temp down to 29 degrees. Also A couple of sites said they liked a humidity of 80 to 90 percent. They do move around more during hibernation to seek water I have read. I have practically no experience with big browns, so
I just search and read on the computer. You have certainly done more than anyone I have ever read about to help the big browns. I think that if you kept the room very humid where the stud wall is located , and 32 to 40 degrees the big browns could tolerate those conditions. That's just my gut feeling, nothing to back up my opinion.
Since you have worked in HVAC you know that heat travels from hot to cold always. Also I believe the water vapor will also head out into the stud space since it won't have a vapor barrier. I used to know a lot more about hvac but have been retired for 15 years and tried to forget all that stuff when I quit work. I have begun to think that we sometimes try to help wildlife when they already will look after themselves.
I used to have brainstorms for solar bat houses with thermosyphon heating systems, etc. but now think the standard old bat house design is
OK built in several ventilation and color schemes for spring, summer and fall plus winter for a few bats that move around then.
Good luck with your project. I have been missing your previous frequent posts. You seem to be a guy who takes action, like Terry Lobdell
and not just a talker.

Frank

[Terry Lobdell]

Nate, I've considered building just such a bat house within the exterior of my house.......I'll be interested to see how your's turns out!

[William Bagwell]

Nate, I've considered building just such a bat house within the exterior of my house...

Ooh, add an observation window and this is something I would be interested in. Darken the room a bit, raise the cover flap and peek in on the little critters. Have the perfect place for one in our upstairs...

Edit: Doh! Totally missed the sentence up thread where Nate said he was doing exactly this with pet mesh. So since that is a bit had core for me and I would prefer not to share my air with the bats.

Wonder which of real glass, Plexiglas or polycarbonate would be best to use for an observation window?

William

[IowaNate]

Currently it's 40 degrees outside, and the temperature in the stud cavity is 47 degrees. The humidity level is only at 35% though...perhaps a simple pot of water in the crawl space will help raise the level a bit through minimal evaporation. The temperature in the actual living area of the attic is 58 degrees.

[IowaNate]

The stud cavity that is screened off for bats is now inhabited by a big brown bat. The temperature in the space is currently 88 degrees.

[cloudman75]

I have wondered if you ever got a bat in your wall house. Congrats on the success Nate.
Thanks for the post and updated info.
Frank

[IowaNate]

The wall cavity has been a success throughout the Summer. Granted, I have only seen two big browns using it at any given time, but this Winter should prove interesting since the access into the house has had a full year for the bats to get used to it.

[cloudman75]

Hello Nate,
Good to hear from you on the wall roost. That is so very unusual. Randy in Lousiana and I were talking on amateur radio last week and one of your state's amateurs requested some info from me on bat houses. He overheard us discussing bats. I received an email from him later and invited him to the forum. He lives in Sharon Iowa. I sent him a couple of plans for bat houses. I hope he comes on the forum so if you see Dan from Sharon, give him some advice please. Hope all is well at your place Nate.
I have not had a year to brag about, but had some bats.

Frank

[Joe Spencer]

Ya looking forward to updates Nate! Hope all is well!