Bat House Forum

[kh67]

Hi, all!

We've had a couple bat houses for a few years now, one freestanding in the back yard on a metal pole and one mounted to the back of the garage at the peak of the roof.  We've had minor success, only having between 1 and 3 little brown bats at a time in either house, and I presume those are bachelors.  The pole house is actually two houses mounted back-to-back, and it was from the BHB Handbook I had checked out through our library.  Its on the small side, though it seems the plans called it a nursery house.  The garage bat house is a very plain single-chamber experiment that we put together without any plans to see if different dimensions gave better results.  Its a little wider and taller, though I suspect the single chamber means a lack of temperature stability.  The pole house is painted dark gray (nearly black) and the other is a deep brick red.  Both are oriented to the south.  Sorry that I have no dimensions to offer.  I'd probably be way off if I guessed.

We live about 3/4 of a mile from a college that last year had a bat house mounted on a tree on campus.  Everything about the location was "wrong."  It was facing north, surrounded by trees and buildings, was right by a parking lot and a lot of foot traffic, and was reasonably well-lit at night.  Oh, and it was an itty bitty thing.  Yet, I counted upwards of 40 bats come out of that house, having lost track because they were coming out so fast.  I was sad to see this spring that the house is gone--not replaced, GONE!  I mention this house because it shows that there are (were) a lot of bats already in town, just not in my immediate neighborhood--apparently.

Now, my question is this: I want my husband to help me make a nursery house that is bigger than what we have in hopes of attracting a colony.  Does it make a difference how close a bachelor roosting spot is to a nursery house?  Can they be back-to-back on the same post, for instance, a nursery house on one side and a smaller house on the other with bachelors?  Anyone know why they roost separately?  Do they not get along?  Too, is there a size for a nursery house that seems to be more successful?  I've seen IowaNate's plans for 3 houses from the same piece of wood, but are those minimal dimensions for economy?  My husband isn't keen on building me another bat house, and I'd like to take my best shot at success, since it might be my last!!  ;)

[Terry Lobdell]

Welcome! The fact that you already have had bats roosting means you have a good chance at attracting more.

That is interesting and very unusual about the bats roosting in a tree mounted house.........most likely there is a large colony nearby. I have observed many little browns roosting in some bat houses at a state park mounted in partial and some in total shade........I'm sure the reason is they are right next to an old farm house where we've gotten counts of up to 800. If you are right near a huge colony they will roost in just about anything.........if you have no maternity colonies close by it will take longer to attract one.

Why females and bachelors roost separately I'm not sure. Maybe because the females need higher temps to raise their young.

It sounds like you are on the right track. My belief is the more options you give the bats as far as number of bat houses, orientations like east, south and west the more bats you will attract. Many choices in design which affect temperature range and ventilation is important too.

My maternity colonies, both little and big brown both love mesh covered baffles especially when pups are young.

My maternity colonies also prefer houses with at least 3 crevices. The bigger the bat house, the more heat it will retain through the night. This is very important in June when night time temps dip down into the 40's and the days are overcast with temps only in the low 60's. The middle crevice of these houses probably stays fairly warm as the outer two crevices would act to insulate it.

Back to back mounting is always good especially if you have access between the two houses. I and others have a lot of pictures on here that show advantages of different designs and mounting locations........hopefully we can answer all your questions!

[kh67]

Terry,

Thank you for taking the time to respond to my questions.  For all that I've read about bats, I feel like I know so little.  Its SUCH good news that there is still hope for attracting a maternity colony!  I was afraid I was out of luck since we had so few bats hanging around here.  (Pardon the pun.)  Now I just need to talk my husband into buying and cutting some wood for me. 

[IowaNate]

 Welcome to the forum! You mentioned my nursery houses that I designed from one piece of 5/8" plywood, the dimensions are just a few inches above the minimum guidelines that Bat Conservation International recommends and the house should easily be able to accommodate 200 bats. And I consider three chambers to be the minimum for good success at attracting nursery colonies.

  Since we are in the same state and close to same latitude I would recommend a dark colored house (deep brick red as you mentioned seems good) with at least one vent in the front chamber for best success.

    On the subject of why non-nursing and male bats roost separately than in nursery colonies, most research suggests that the nursery colonies like warmer temperatures as Terry pointed out.

  If you did decide to make three bat house as per my design, I would mount two back to back with a space in the middle creating basically a larger 7 chamber house in the spot where your current pole is...then mount the other in place of the garage mounted house. Or if you have the extra time, mount them similarly but a few feet away from the current houses.

  With all this being said, I am still a firm believer in being 1/4 mile or less away from a large water source to have the best success at attracting nursery colonies. And given my observations, I consider a major water source to be a creek at least 15 feet wide or a pond that is at least 2 acres.


 

[IowaNate]

 Here is a link to my new bat house design which is a standard nursery/semi-rocket house hybrid. This house has desirable features to many different types of bats. The two I built are proving to be VERY successful with over 300 bats in one house at my last exit count.

  http://www.batnic.org/forum/forum3/398.html

[kh67]

By your definition, I can't say there are any major water sources in town at all, but that certainly hasn't stopped the bats from moving in, at least near the college.  I've also heard that they roost in the steeple of a church a few blocks from the college, though I haven't witnessed them myself, as the glare from the street lights make it difficult to say for certain if what you are seeing are bats or birds.  We do have a public swimming pool about a half mile from here, and there is a very small creek varying from about a foot to 3 or 4 feet wide that runs along the edge of our yard and across the street, though its virtually stagnant in some spots.  There are trees on either side of it on my side of the street, but once it crosses the street it is open on either side for a stretch that I would guess is at least 75 feet.  Of course, its much fuller after a rain.

We bought a year and a half ago 5 acres of raw, overgrown land down by Chariton that we hope to build on someday (an earthship AKA tire house, if that means anything to anybody).  Its about a mile from the Rathbun Reservoir.  I've been itching to put a bat house down there and see what happens.  Beyond the reservoir, I have no idea what water might be around.  Hmmm.  I wonder now if a bat house down there would be futile.  Of course, it won't stop me from trying. 

[IowaNate]

 Definately keep trying no matter what the distance from open water as long you observe bats in the area. Two of my successful houses were more than 1/2 mile from any source of water and had bachelor bats occupying them.

  The simple fact is that you have a few bats roosting in your bat houses already, so definately put a few larger multiple chamber houses up to see if a larger colony moves in...and if more don't move in, then you have a better choice of safe roosts for your current bats. :D

  I personally love to see photos of bat houses on this site and how they are mounted, so if you could post one or two it would be great!

                                                                Nate

 

[cjacustomwoodworking]

We live about 3/4 of a mile from a college that last year had a bat house mounted on a tree on campus.  Everything about the location was "wrong."  It was facing north, surrounded by trees and buildings, was right by a parking lot and a lot of foot traffic, and was reasonably well-lit at night.  Oh, and it was an itty bitty thing.  Yet, I counted upwards of 40 bats come out of that house, having lost track because they were coming out so fast.  I was sad to see this spring that the house is gone--not replaced, GONE!  I mention this house because it shows that there are (were) a lot of bats already in town, just not in my immediate neighborhood--apparently.

 

Too bad that house isn't there any longer, proves that bat houses don't need to be enormous to work.  In the UK, a lot of houses are mounted in trees and are smaller.  My buddy in Liverpool makes small bat houses, he was quite surprised when he came over to the USA and saw my houses.  People forget the most important thing is to get the house up.  We are in such an infancy with bats that I think it stands to try different things.

[IowaNate]

  The small creek near your home could be enough to encourage more bats to use the bat houses in your yard. I read an article recently that said bats generally need a 12 foot open flight path on the water when drinking, so if there was a stretch of the creek that long and at least 3 feet wide close by, it may be suitable for bats to drink from.