Bat House Forum

[IowaNate]

   Here is the inner box. Basically a four chamber nursery house with two 3/4" by 6" slots in the rear chamber and one 1" slot in the front chamber. The dimensions of this box are 17.5" wide and 24" tall. The slots allow bats to access the outer wrap around chamber.



   Inner box placed in the outer shell  (prior to screening). The outer box is 20.5" wide by 30" tall.



Inner box fully screened and installed. Note the top portion of the outer chamber is not screened (ran out of screening) so I roughed it up with screws.



   Finished house with view from underneath to show all of the chambers. There is also a 1/4" vent in the front of the house 6" from the bottom. Chamber widths from back to front are 3/4" 3/4" 3/4" 7/8" and 3/4", the sides of the wrap around chamber are 1".

   I designed this house to give a much greater range of temperatures and to allow the bats to access more chambers with the option to "follow the sun" or get away from it. I made a few larger crevice widths to perhaps attract a few more big brown bats which do show a slight preference for 7/8". This house is replacing my smaller nursery house which is 14" wide and 24" tall with 4 chambers and houses 250 little brown bats (and a few big browns). This new house should be able to hold 500 or more bats.  It will be hung this November to give the house time to rid itself of the paint smell and be ready for the bats arrival in April. My main goal is to get both little and big browns to form nursery colonies in the same house. I hope they like the new home much better than the old one!!

[IowaNate]

 Please give thanks and/or a contribution to the Indian Creek Nature Center for thier work to promote and secure wildlife habitat. They have given me the opportunity to do my bat house research for over ten years now...I can't thank them enough!   Here's thier website if you are interested in contacting them.

http://www.indiancreeknaturecenter.org/

   Thanks to everyone for supporting our little winged mammals of the night!

                                                                 Nathan Krejci

[Terry Lobdell]

Nate, that is a very clever design..............it gives has the advantages of both a rocket and conventional multi-crevice design........Thanks!

[IowaNate]

 Final weight on this house is 32 pounds. I try to keep my houses as light as possible since I am usually hanging them alone. The newer tip-up pole design for mounting seems like a great option, though I don't have too many spots to put one.

   Luckily this house is being mounted on a corner post (6x6) of an elevated deck. The deck is 10 feet off the ground already and the post extends 7 feet above the deck, so mounting this house about 15 feet up is no problem.

   There is a 30 foot wide creek (Indian Creek) just a hundred yards away, and the Cedar River is just 1/8 mile away. The immediate area is forested, and some prairie and wetland area within 1/4 mile. Between my two bathouses that have been there for about ten years, I have a nursery colony of roughly 400 little brown bats with a few big browns sharing the houses. Hopefully these new houses will expand the colony to over 800 bats and perhaps even entice the big browns to form nursery colonies. I have seen an Eastern Pipistrelle roosting in a 5/8" gap under the deck but have never seen one in my houses. Perhaps these small bats like crevices smaller than 3/4" inch. One last note, I have noticed a few bats the same size as my little browns, but with a bit longer ears, perhaps they are Northern long eared bats (Myotis septentrionalis).  I know they share similar habitat and behavior as the little brown but I have yet to 100% positively identify them. A few of the longer eared bats have been nursing young in my houses. I would be so excited to find out that I have nursery colonies of two different species in the same house!!!

    This summer I will try to get good photos (any ideas of good cameras?) of the bats using my houses at the Nature Center and hopefully get some help in identifying this mystery bat.

[IowaNate]

  Here are the current houses at the Nature Center which are being replaced. They are visible on the corner posts of the deck.



   The house on the right is home to the larger colony of little browns (250). Below is a close up showing the need for replacement, the fiberglass window screening is in bad shape as well.



  Below is a close up of the house on the left. The exterior is in good shape, but the fiberglass screening is sagging and missing on most of the partitions. This house is slightly larger, but has never had as large of a colony (150 to 200).

[Joe Spencer]

Very nice!  Nate, since these were occupied the lights on the opposite sides of the pole obviously didn't discourage them from usage.  How far is the water source (creek?) and how substantial is it at this site?  Thanks again for the great photos..

[IowaNate]

 The creek is about 30 feet wide at the site, and the river is over a hundred yards wide, being only 1/8 mile away. I can throw a rock from the bat houses and hit the creek.

  The second wrap-around nursery house is finally done. Each of these new houses took about 8 hours to complete. The staff at the Nature Center is very excited that the replacement houses are going up, and should increase the size of the colony twofold.

  I will be taking apart the old houses and documenting the wear (with photos) on each house since they have been up for about ten years. I will have photos up by next week!


              UPDATE!!!

   Old houses are down and new houses are up. I have photos of the house that usually held 250 little browns. The first pic below is with the front of the house removed showing the first chamber. About 75% of the screening was intact and surprisingly most of the staples were intact (though badly rusted).

    

     Below is a photo of the rear chamber showing numerous dead parasites, mostly bedbugs with a few fleas and ticks. This is definate proof that parasites can be a major problem with large colonies and persuade them to switch roosts occasionally.



   The last photo below is of the house and all of it's partitions separated. The smell was quite overwhelming. I am thinking if cutting a few of the old partitions into small pieces and attaching them temporarily to the new houses (perhaps to the landing area) to give it the familiar smell. Is this a good idea?



    The second house was in similar condition so I didn't see a need to post photos. The houses had partitions made of 3/8" unpainted plywood, and although they were badly stained and soaked with urine, showed no real signs of damage or warping. The main problems were not having a good exterior paint job or coating, delapidated fiberglass screening on the partitions, and too few staples used to attach the screening. I did not use treated or stainless staples in the construction of these old houses and most of them were still holding the screening in place. I am a firm believer now that you should staple screening every 2 to 3" if that is your method for footholds. My old houses were stapled approximately every 4 to 6" which caused alot of the sagging and tearing of the screening due to the weight of the bats.

   Taking down these houses has gained me alot of knowledge for future construction and durability of my bat houses. These houses were built and installed when BCI's Bat House Research Project was just getting started & many things were unknown about consistant bat house occupancy. Over ten years of use by sizable nursery colonies in my houses and much of my other BCI research associates shows me what works and what can fail after a few years.

   

[Terry Lobdell]

Nate, I place staples about every 2 inches. I use mostly stainless steel staples. If I do use regular staples I coat them with poly glue. Sometimes I use a combination of staples and glue because the glue is less expensive.

I have also used liquid nail to attach fiberglass screening as well.

The scent from the old houses may help attract the bats to the new ones. But considering your numbers they are pretty well established there and they should accept the new houses quickly.

[IowaNate]

 Well Terry, to be on the safe side, I am going to cut 4-5.5"x6" pieces of the old partitions and attach two to each house on the inside walls of the landing pad. This should provide some familiar scent, and not restrict access to the new house in any way. I will just use 1/2 staples to attach them, and remove them next winter after the colony has had a chance to re-establish itself in the new houses.

[IowaNate]

  Here's the two new "wrap around" nursery houses mounted at the former site of my old houses at the Nature Center. I managed to get these house about 4 inches higher than the former houses. The new mounting technique of using angle brackets on the top of the houses made it so the new bat houses were in direct contact with the 6X6 post (the old houses were mounted about 1.5 inches from the post on 1X4's). This may help slightly with temperature stability. The anxiety of waiting untill mid-April for the bats' return is driving me nuts! I will post photos of the occupied houses as soon as the bats start coming back. Here's to hoping the colony increases from 400 bats to over 600 in the next few years!!!:)

 



 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Joe Spencer]

Nate they look fantastic.  We'll too look forward to spring occupancy.  

[IowaNate]

 The Nature Center is letting me put up another bat house near my new wrap-around houses. I wanted to put an extra wide house (36") just below the attic vent, but they had concerns of guano dropping on a water spigot. So I sent them this photo of the proposed site with a smaller bat house off center so the guano will fall about three feet away from the spigot. They love this idea, and said I can put one up any time. This will allow me to mount the house on the building with 1x4s and create an additional roosting space against the wall itself and the roof overhang will protect it from the elements. Perhaps a few more big browns will use the cooler space. I will be mounting my basic 4 chamber house here that is similar in size to BCI's. If this house is as successful as the other two on the deck, the colony could easily reach up to 1000 bats between the three houses in the next few years. It will be quite a site to see the bats emerging on a warm summer's eve!

 

 

[BatMan]

Very nice Nate. You know, two rocket boxes would look nice installed on the top of those 4x4's as well.

[IowaNate]

  First update on the new houses. Due to the slope of the ground the East (right) house is 13' 6" from the ground, and the West (left) house is 16' from the ground. I still gained 6" of height on both new houses as opposed to the former houses and kept them on the same horizontal plane to make it look good on the corner posts.

  The East house has one big brown occupying it already and it is the rear chamber. I was hoping to see a few more bats due the the early occupancy of the houses mounted on my home, but it's still early.

  I am reposting a photo of the former West house showing the large dead "snag" ten yards to the West of the house. It has very few limbs and is about 16" in diameter and 18 feet tall, this would be another great place to mount a house. Granted it would have increased chance of predator problems, but has great potential due to it's lack of limbs and complete sun exposure throughout the day. I can easily trim the small dead branches as well. Even though it is a tree, it would be more like a large post mount. I am planning on an experimental house design for the snag, and any feedback on ideas would be greatly appreciated!

 

                      Nate

 

[IowaNate]

 Here is a simple and inexpensive design that would be very suitable for the dead snag. I would be using 3/4" spacing though and saw kerfed baffles creating 7 chambers. It could easily hold up to 400 bats, and be constructed in about two hours and cost less than $20. I would also include a vent 6" from the bottom of the house and 1.5" passage holes in the middle of each partition. I would mount this house facing East to get the morning sun, and then the sun would warm the South side of the house throughout the midday due to it's box shape. Also being made completely out of 3/4" lumber it would have great thermal stability. I could also incorporate a concrete block as the ceiling of the house.

  These plans are directly from the Pennsylvania Game Commision's website and I hope by stating this that I am not breaking any copywrite laws.