Bat House Forum

[WolfmansBrother]

Hey everyone, great forum!

I am in the process of building a couple of double chambered rocket boxes for me and my neighbor:

The area that i will be putting them in is not perfect but should work well. Pretty good unobstructed line to the south east. Only problem is the 2 story condos to the east that will block some of the morning sun, but should recieve at least 7-8 hours of direct sunlight.

The houses will be 4ft tall on a 5ft 4x4 cedar post, then conected to a 16 ft treated 4x4. 4ft of the treated post will be in the ground for foundation.

The houses will be double chambered.

The choice of rocket boxes is for appearance.

I live about 150 yards from a lake.

My questions are as follows:

The general design that i am using is for a single chamber rocket box and they have just one vent at the top. I have seen designs that have vents on the bottom or on the top, wondering which would be better, or both or some other solution, especially with mine being 2 chambered.

Most places that i read about bat houses say that the house should be at LEAST 12ft tall. But i have yet to hear if that means the entry point should be 12ft or not.

I live in north west iowa and according to the coloration maps that i have seen we are just on the edge of the dark-brown and straight black painting line. It gets pretty hot here in july, i would guess that it averages around 85-90 but this is Iowa, we never quite know what we are going to get year to year.

I have seen mixed results on whether i should put cut out "roosting spots" on the post in the house. I heard, from someone on here I believe, that they are unnessasary and just invite wasps, but most designs that i have seen include them. I think i am going to make one of each and see what happens.

Being that it is a 2 chamber house should i put ports between the chambers, and where should i put them.

Any advise that you guys have would be greatly appreciated. I want to attract bats, not worry about my pride, so dont be afraid to point out things that you think are wrong.

I know thats a lot to swallow, thanks for reading it.

[Dave M]

Greetings Brother of Wolfman!

I'm pretty new to bat houses and am just building my first one now. I live in SE MN, so we're not terribly far apart. Like you, I'm experimenting with something different, but trying to use the knowledge that's available. You can search this forum and get an idea of what I'm trying to accomplish.

I just took a look at range maps for bats, and am guessing that you'll be trying to attract big brown bats and/or little brown bats. Most of the stuff you read about pertains to little brown bats, and it seems that they like to use 3/4 inch chambers. After doing a lot of searching and getting helpful advice from people on this forum, it seems like the big brown bats like using 7/8 inch chambers, and like to be a bit cooler than little brown bats, and like to have more ventilation also.

As for the color of your house, you could go black and use more ventilation, or just something dark with normal ventilation. If you try both chamber widths, you could give the wider ones more ventilation for the big browns.

[Dave M]

Take a look at "The Bat House Builder's Handbook" by Merlin Tuttle, if you haven't already. I checked it out from the library.

[Terry Lobdell]

Welcome!
Your design choice is a good one.......I built one like that last year and had very good results........

If you have a height of 12 feet above ground to the bottom of the box that should be plenty of height especially if it is mowed lawn underneath........

You might want to reinforce your post at ground level......that is a lot of weight and could snap off in high wind......or maybe go with a 4x6 or 6x6.......

I would have the vents at the lower 3rd of the box...........on all 4 sides........

I live in roughly the same latitude as you being in NWPA........I used make all my boxes flat black but have observed that a nice chocolate brown is plenty dark enough and is more asthetically pleasing........
Another thing about color.........little browns get much of their warmth by roosting in high numbers to conserve body heat......
Big browns like it cooler anyways so the darker color is not necessary for them..........
The large size of your box will have more of an affect in creating the desired temperatures than the color will anyways......the greater the bulk of the box the more it absorbs heat during the day then slowly releases it throughout the night.......

I absolutely would not cut in roosting spots/notches because they are not necessary and most certainly will attract wasps.........
Believe me........bats get nervous with any crevice larger than one inch.........I have around 70 boxes at various locations on my property of different designs.......bats are most comfortable in crevices where they can jam in tight together......
The old rocket designs with the notches are very outdated........

The ports between chambers could be at the lower third of each side.........bats definitely love ports in crevices so they can change crevices internally.......

Your proximity to the lake sounds really really good........I think you have great potential with your habitat and your design.......

Here is a link to pictures of a double crevice rocket box I built last summer........the design you have described sounds similar to mine.......although mine is not the best looking with the old hot water heater lid for a roof. However, it is not visible to the public so I just focused on efficiency rather than looks.......

rocket-box-with-partitioned-crevices-t861.html