Bat House Forum

[Joe Spencer]

Soffit houses below have no roof. The perforated soffit itself is the roof and also provides heat and air. One bat house has cement core partitions and the other rough pine. Hopefully next year once occuppied the bats will reveal a preference. These houses will receive direct morning sun (eastern exposure) with afternoon shade however, warmth will be provided throughout the day from western roof heat on opposite side. My goal is to attract a nursery colony with this soffit design. They have a sizable painted white area so as to be to the liking of Big Brown bats which are known to abandon roosts once temperatures exceed 95?F:



You can see the perforated soffit better in this photo:



Shown below are the 1/4" hardibacker cement partitions I'm experimenting with below. I also recycled the shell of this bat house from one I made a few years ago (The stainless steel staples I used have been flawless after all these years. The rear and back plastic mesh never sagged and still retains its tautness:



Below is top of bat house which abuts soffit. It is lined with a brown foam sealant weatherstrip used for windows and doors. It creates the seal between soffit ceiling and bat houses.

[brockbat]

Hey Joe, Did those soffit houses ever get occupied? I have the option of doing the same but thought there might be too much draft going through the house. Maybe you could post an update.

    Brockbat

[Joe Spencer]

YES they are!  During the heat wave we had last week the bats went from the rocket into these soffit houses.  Appears to be only two bats.  These bat houses only receive morning sun until about 10:30 am.  Thereafter they don't receive direct sunlight but receive steady not overwhelming residual warmth from the soffits and the lower heat of the attic which I'm finishing off for living space.  I still see a little guano each night below the rocket as well but a few more beneath the soffit nursery houses.  If I had to pick a preference it appears there is a little more guano beneath the rough solid pine parititioned bat house which is the shortest of the houses in the side by side photo above.  It is likely that I have male Big Browns which like it cooler than myotis bats and will abandon a roost when temperatures exceed  95 degrees.  That is always the challenge: to build a bat house which can meet the temperature needs of common species and try not to exclude any of them and their preferences in your design.  It reminds me of something that happened a few years ago in the photo link below.  One of my bat houses had cracked along the side which didn't allow rain in but actually acted as sort of a side vent on one of the side by side nursery houses I had mounted on a dead tree.  Guess what the greatest number of bats preferred, the cracked house.  Could have been a coincidence who knows.  Could be because they were big browns bachelors which prefered it cooler.  REGARDING THE DRAFT  Maybe the fresh air isn't bad as long as it doesn't quickly or dramatically effect the temperatures of the house.  I thought Kent Borcherding (bat house premier) once mentioned something about air movement being a positive thing hope he catches this post to elaborate.  Anyway I'm still not sure but here are the bat houses on the tree I mentioned I previously had up:

Nursery houses:  http://www.batnic.org/bigimages/treehse100.html

Bats in them:       http://www.batnic.org/bigimages/batsinhouse100.html

[Terry Lobdell]

Hi Joe,

I like your idea with the cement board. I have a couple questions. How far apart are your grooves in it? And did you darken it at all?

Thanks,

Terry

[Joe Spencer]

The grooves are 1" apart and they already come on the board as part of the manufacturing process.  Ideally you would want more I guess but after knowing in Texas I believe that bats are using concrete houses built into bridges without a scoring I assume, I guess the 20+ horizontals per 2 ft. on these partitions are better than nothing.  NO Terry I didn't darken the partitions although I think a non petroleum based black water stain would probably be a good idea and maybe worth experimenting with huh.  :rollingeyes1:

[Terry Lobdell]

Thanks Joe,

Got a couple more questions:

 For interior stain, has anyone come up with a brand that may be the best to darken the interiors of bat houses? I have experimented with this a lot and it seems like  I have to choose a happy medium between  darkening the interiors and leaving the wood rough and easy to grip. I'm coming to believe that bats strongly prefer roosts that they can grip firmly no matter where they reach......Seems like latex stains fill in the grain even when they are thinned. This is on baffles with saw kerfs every 3/8 to half inch.  My bats continue to show a preference to houses which have mesh roosts. These are both fiberglass screen mesh and black plastic cross-stitch mesh. Both are finely woven enough that absolutely no guano gets caught. I would like to just go with saw kerf baffles to avoid the corrosion free fastening issue but have yet to find a stain I am happy with.

I saw somewhere that food coloring was recomended. Has anyone tried this out much?

Thank you,

Terry

[Joe Spencer]

Has anyone yet tried food coloring for darkening partitions?  If not I'll try it as soon as I can.