BCM Double Chamber Bat House
QUESTIONS & ANSWERSAsk BCM a Question
How many bats does a Double Chamber bat house hold?
The rule of thumb on most any bat house capacity is to add up the length of the linear roost crevices, then assume a safe holding capacity is 2 bats per inch.
For the Double Chamber bat house, it is 18'' wide with 2 chambers, so that is 36'' of roost space. Multiplied by 2 bats per inch is 72 bats. If Mexican free tailed bats or Myotis spp. move in, they may double stack the wide crevice bringing the capacity close to 100.
A Single Chamber bat house at 18'' wide will hold ~36 bats.
A Triple Chamber bat house at 18'' wide may hold ~108 bats.
The 4 Chamber Premium bat houses at 18'' wide on paper may hold 144 bats, but the Universial model is a special beast with a clever baffle cluster inside. If a myotis spp. or Mexican free tailed bats take up residence, there may be upwards of 210 bats due to the way those bats "double stack" in a wide crevice and when the additional "attic space" is accounted for.
You can use the "2 bats per inch" rule with other manufacturers bat house and test their marketing claims, as sometimes this figure is exaggerated.
My kit included two pieces of 3/8 plywood - roughed. About 8”x2” What are they intended for?
The two pieces of wood you are referring to are “pup ledges”. Nursing females will leave their young in the roost for short periods to forage for insects. Although nursing pups rarely loose their grip, it does sometimes happen when they awkwardly move around within the bat house during this time or are knocked loose by other bats in the colony. The pieces of wood act as a small ledge on either side of the baffle to give the pups something to grab onto if they lose their grip at the top of the bat house. Please refer to the PDF assembly manual for instructions about attaching the Pup Ledges. We offer another product called a Pup Catcher as an accessory if you observe a chronic pup issue. This is much larger, more robust "basket" intended to go below the entire bat house. Pup Ledges in contrast are small wooden ledges inside the bat house between certain baffles.
I just wanted to confirm double chamber boxes will work for this area because your website says the 3 chambers are better.
Yes the double chambers would work anywhere in the US. The larger chamber is ideal for big brown bats (found almost nationwide) and Florida bonneted bats. The narrower chamber is great for a host of species that prefer smaller 4/4'' crevices, such as little brown bats, northern longear, Indiana bat, Southeastern bats, cave myotis, and Mexican/Brazillian free tail bats, to name a few. Just install in a sunny location as the smaller mass of the 2 chamber makes placement a bit more sensitive.
How high above the ground should I set up my bat house?
The bat house should be situated at least 10’ above the ground.
What color should my bat house be?
Because bats need an adequate amount of warmth during the day, solar exposure is very important when setting up a bat house. However bats can also get too warm, so coordinating bat house color with your geographic location can aid in having a successful bat house. Refer to the temperature zone map located on our Four-Chamber bat house page.
Cedar vs. yellow pine wood for the most durable bat house and lowest maintenance?
The wood thickness has something to do with it, how many screws are used to hold it all together, and how well the bat houses have been finished (how many coats of paint used, etc.). So, material is actually not a big player in this in my opinion. True cedar may be more insect resistant, but either box will probably fall apart from normal weathering long before insect damage comes into play.
BCM pre-scratches all interior surfaces of all kits in multiple directions, so bats have the maximum ability to hold on. We do not use screen that bats can become trapped under.
The longest lasting bat houses will be the plastic shells such as the Four Chamber Premium.