Bat House Forum

[cloudman75]

When one may think he/she knows a lot about bats, they do something to surprise you. WE have been out of town four days, so tonight after dark I shined a light up into my houses. I was shocked to count only eight pups, when before there had been so many I could not count them. It has been very hot here in the high 90s so I just assumed the mothers had
moved them to a cooler spot as they cannot fly yet. They are getting large so that It is amazing to me how the females can fly carrying the large pups. I went out a little after midnight to see if the eight had disappeared and to my surprize all
the pups were back. We had cooling showers tonight so that may or may not be why they are back. Anyway they all appear to have returned. From the looks of the pups, they should be flying in a week or 10 days for sure. These are little brown
and some freetail pups roosting together.

Frank

[Gary Springer]

I don't know what state you live in, and I'm sure the requirments change from state to state as well as from bat species to bat species, but I think most bat houses are designed to be way too hot. I know, that is what BCI calls for, and paint them black!!!!!

I live 60 miles south of Tennessee. I put two or more ventilation slots in my bat houses, and they love them.

The distance from the top down to the first quarter inch ventilation slot is 7". Then there is a half inch slot down another foot.

That gives any heat seeking bats 7 full inches to crowd together at the top of the house. A lot of bats can fit in that area. And, when it gets hot, they all have access to as much fresh air as they want.

These bats can take temperatures below freezing. I will never believe that bats like temperatures of 140 degrees. And, if you put up a bat box with the designs I keep on seeing, it willl exceed that temperature very rapidly on hot sunny summer days, even if you live in North Dakota.

I even have one bathouse that is falling apart with half inch ventilation slots every 6 inches, and they love it, and they raise pups in it. There's only 4 inches at the top that doesn't have access to free moving air.

Another thing I do to keep my bat houses cool and dry is to put a tin roof on top with an air space between the 3/4 inch thick wood roof and the tin. There is an overhang of more than ten inches all the way around on one of the houses. That keeps the sides of the houses in the shade most of the time. There are more than 150 bats in that house.

One more thing I'd like to add. My bats are all made from 3/4 inch very very rough sawed yellow pine. I don't use any paint at all. When they are new, I rub charcoal over them so they are not so white. After a couple months, the wood is simply natural gray weathered pine.

The bats love to cling momentarily onto the rough outside surface of the bathouse at night. I can not imagine that a bat house that has a beautifully painted slippery finish is any way near as attractive to bats as one that is rough. A bat house that is properly constructed with a good roof will last ten years. Considering how cheap this hobby is (no food needed, just put up the bat house and watch) Don't you think your bats deserve a new bat house every ten years? Forget the paint! And, forget the toxicity of cedar that emits plycatic acid.

I have more than 400 bats now, and one is pure white!

I really believe that the number of bats here is restricted only by the amount of living space inside the bathouses.

Gary Springer

[Dave Miller]

I'd love to see some photos of your bats and bat houses, Gary!

[cloudman75]

Gary,
I live in Georgia west of Atlanta right out past 6 flags near I-20 not too far from you. Actually BCI and others have a color
to paint your house depending on where you live and how hot it is. I have three houses. Two are ventilated, one is not.
One is unpainted cedar, one is plywood painted a light blue latex to make it last and is about 5 years old. I built it and put a ceiling in addition to a roof. It has a brown fiberglass shingle. I posted photos on the forum last winter when I relocated them further away from my house in the back yard. In the spring when temps are cool, the ventilated houses are too cool
for pups in April here. I built a third house, painted the top half dark blue almost black, and the bottom half light blue.
This was just an experiment. It has no ventilation.
The bats arriving here in March use the house for a few weeks at times because it is warmer and unventilated. When it gets hot, they don't use it and move to the ventilated houses. At present I have a maternity colony of 105 adults at last count. They have pups and some are flying. These are little browns and a couple of dozen freetails. I have had freetails here in my unventilated house in winter. I posted photos of them on the forum this past winter. My bats started out in my attic louver as a maternity colony of 17 about 6 years ago.I excluded them when they left and installed my first bat house. They have grown to a number of around a hundred. I have about 200 leaving here in Nov. I don't know why only a hundred come back. I guess some are males and some don't make it through the winter. There are several bat caves listed by GA. DNR about 30 miles from me in Bartow county. I often have my little brown bats leave for a couple of weeks in July or August, then return and stay until Nov. They can be at their cave in an hour. I think they swarm with other bats at times. My large 5 chamber which I built has 4 ventilation slots, two in front and two on the sides. The bats have enjoyed this house, but don't move into it until around the middle of April or first of May.
I agree with you that bat houses in our area don't need a dark color. I plan to paint my unventilated house white this winter and put a lot of ventilation in it as another experiment to see what the bats will do. I also plan to install a couple more bat houses and have already started gathering materials for them. Glad you are posting on the forum, as you appear to be doing it right.

Frank

[cloudman75]

Gary,
I forgot to mention that I have never heard, read about or seen a white bat in Georgia. I would suspect that is a rare one. We all would be anxious to see a photo of it. Also if you will, please post photos of your bat houses. I, like Dave Miller would be interested to see them. My bats have never shown a desire to land on the outside, and in fact usually don't use the landings I provided but just swoop up into the houses . There are photos of my houses under photos of this forum.
They are holding up pretty well so far and still in good shape.

Frank

[LarryH]

When we were touring Bracken Cave a couple years ago, someone asked about albino bats, and as I recall they said that there are about 1 in every 2 million Mexican Free-Tail bats. But, nobody there had ever seen one. It would be cool to see.

[Terry Lobdell]

On the subject of bats coming and going, Mine move all the time........especially my big browns.........recently in this hot weather they have been moving about every 2 days..........they rarely stay in the same box for more than 5 days........

Last year my big brown bat maternity here at home used 12 different boxes throughout the summer!

My little browns move much less often..........

[Gary Springer]

About the white or albino bat:

I've seen the white bat 7 times now. Of the 8 times I've watched the bats exit, it has exited one bat house 6 times and another once.
Sure would like to know more about this bat but I can't get any one interested in coming to look at my operation despite trying for more than two years.

About CEDAR

I think it is a huge mistake to make a bathouse from cedar because cedar(ESPECIALLY WESTERN CEDAR, the cedar from which most bat houses are made, and including the more aromatic cedars such as the Eastern Red Cedar) These woods emit plicatic acid no matter how old the bathouse is. Plicatic acid destroys the lungs of warm blooded animals and there is a good chance that you will become asthmatic or increase the chances of cancer if you machine enough of this wood in your shop. It is the cause of more occupational asthma than any other substance. Bird house makers that used a lot of this wood argued with me about this. Now, one of them gets sick when he goes near a cedar nestbox, and another has died before age 50)

Since the amount of plicatic acid emitted from cedar wood of all kinds is directly proportional to the temperature, and inversely proportional to the amount of ventilation, perhaps the reason bats leave when it gets warm is a function of not only heat but also toxic fumes.

VENTILATION

All my bat houses are either one or two chamber. That means that all chambers of the bat houses are ventilated by the horizontal ventilation slots across the entire width of the bat house. And, with the exception of an inner chamber of a 36 inch tall rocket house, they all have between two and 3 ventilation slots running across the entire width of each chamber.

If you are using a 5 chamber bat house, the interior chambers don't get anywhere near as much ventilation as any of the chambers in those the bats here are using in both hot and cold weather. Since these bats occupy these ventilated boxes with large overhanging roofs that shade the box most of the day, since these bats occupy these well ventilated bat houses in temperatures between 30 degrees and 100 degrees, my opinion is that the belief that a bathouse isn't being used because it is not warm enough is simply a MYTH. Like so many other myths, we've heard it so many times we don't question it, even if there is absolutely no proof at all.

I would like for someone to show me a natural cavity that achieves temperatures as high as ANY BCI design house. The temperatures inside a bat house on a hot sunny summer day in New York will be just as hot as one in the mountains and foothills of North Georgia, especially if the one in New York is painted black. Furthermore, in my opinion, no bat can exist in such a bathouse if it receives full sun throughout the day, unless they can gather around around the single ventilation slot provided. The number of bats that can gather around a single ventilation slot is very small compared to the total potential occupancy of the bathouse.

Here are some coments about one and two chamber bat houses of about 20 inches wide and 30 inches tall.

If you leave only the top 8 inches of a chamber unventilated, 150 bats per chamber can achieve the same warmth as they can if the entire bat house is UNventilated. If they want more heat, they simply squeeze together toward the top of the bat house in the unventilated area. The body heat of the animlas as well as other heat will rise and accumulate in the top of the 8" UNventilated top part of the chamber immediately below the roof.

so, adding an extra ventilation slot across the entire width 8 inches from the top does not make it any more difficult for the bats to attain warmth than a box that has a single ventilation slot 16 inches from the roof. The extra ventilation slot only makes it possible for the bats to become cooler when it is more than 130 degrees in the top portion of the bat house. And, it enables a larger group of bats to occupy the bat house.

In my opinion, these animals are social and want to stay together. When there is not a ventilated cool zone within a box to accomodate enough of the bats, the entire group will seek another roost.

Gary Springer

Please note that my bat houses are further north than 90 percent of South Carolina, and even further north than a bit of North Carolina. People want to put me in the deep south because I'm in Georgia. But, because I'm at the top of the state and at a higher elevation, the weather here more closely resembles Tennessee which is only 70 miles north of here. (Carnesville, GA)

[Terry Lobdell]

Good info Gary.......especially about the cedar.........I wonder if any other wood species emit fumes that may be harmful as they dry out?

[cloudman75]

One good thing about this forum is that a person can have opinions even if others may not always agree.
I have read quite a bit on cedar and pine. Cedar wood chips and dust are always associated with occupational related repiratory problems and plicatic acid. If you worked in a plant making cedar products with no effective dust collection system,
you would most likely have work related asthma directly connected to cedar dust and/or chips.
The sauna mfg. people say that cedar lumber itself is not toxic or irritable to most people . Saunas operate at very high temperatures and cedar lumber has been used for over a thousand years for saunas. My opinion is that a cedar board cannot sit there over the years and generate plicatic acid as an unending emission forever no matter what the temperature is. Therefore I don't believe that old cedar emits plicatic acid at the same rate as a new cedar product.
I also formed the opinion that cedar lumber is not dangerous to the user. Also cedar is not condemned by the consumer products safety commission for use in saunas where people sit in elevated temperatures.
Thus read, I agree and would think that cedar lumber is a great material for making bat houses. I would think cedar chips and/or dust would be very bad news for animals and mamals. Pine wood chips emit abietic acid which according to what I have read could irritate some sensitive users. I have 3 blue bird houses made of western red cedar and the birds do not seem to mind the aroma. I have noticed after one summer that there is no aroma so I suspect that aging cedar does have less emissions. Some cedar items are constructed with heat treated cedar. I have also read that this is a method of using up the emissions,water vapor, etc. that would occur over time . Of course, I don't know anything about any of this, just have a lot of time to read and form my own opinions from what I read.
I think everthing one reads on the internet must be weighed with some degree of caution. Pine wood has never caused me any allergic problems of which I am aware. Many people have also lined their closets with cedar panels.

Frank

[cloudman75]

Gary,
I caught your site at realbirdhomes.com and read your name in other sites about plicatic acid, etc. I did not know you were so famous. Sorry to disagree with you on some cedar wood projects, especially bat houses. I use pine because it is cheaper but wish I could use cedar.
As I understand it the auromic cedars are not so good, but eastern cedars are not that bad and often used for bat and bird houses by people who claim they are in the know. Keep us posted here on the forum with your bats please.

Frank

[Terry Lobdell]

Frank, thanks for sharing what you've found.........Over the years I've read that many new bat houses are not used for 2 or 3 years because the bats do not like the smell of the new wood. I've been observing 3 large bat condos built by the PA state game commission here in my area the last few years and they are very slow to become used. This is even in excellent habitat with one site having occupied bat houses with 400+ bats a few yards away.

These condos all have scored OSB board as baffles. I have pictures posted of one of them on here. One of the condos built in 2006 did not receive significant use until 2009 when approx. 300 little browns were counted emerging. Maybe there is something in the OSB board that bothers the bats until it is aged a few years.......

Kent Borcherding has spoken often of emissions from plastics and glues in plywoods not being good for bats. I suppose if these materials are aged there would be very small amounts of emissions..........

For me, I've stopped using plywood entirely and just use one and two inch rough sawn lumber.

The two species I use the most right now are red pine and quaking aspen. I do have to watch the red pine for oozing pitch in some boards.

Myself, I have both asthma and allergies. Years ago I used to be a carpenter and sawing douglas fir would cause my nose to run like a spigot! It makes sense that as hot as bat boxes get, some wood aromas might be an irritant to bats.

The past couple years I have been air drying my wood for bat boxes inside my home throughout the winter just to get it as dry as possible before building the boxes. Hopefully this will also decrease emissions that might bother the bats!

[cloudman75]

Terry ,
I think it is a good thing to use old wood and or dry newer wood for bat houses. I had little browns use my cedar house that I bought the first season. It was installed a couple of months in winter before the bats arrived. Here is a photo I hope. You can see the cedar is new. The bats are still using this house, but I never did paint it. We are so hot here in summer that it did not need paint for heat or to preserve it so far.

Frank

[Gary Springer]

I don't want to spend a lot of time discussing the dangers of cedar and the plicatic acid it contains. However, comparing plicatic acid in cedar with abietic acid in pine is like comparing gasoline with orange juice. Both are liquid and that's far as it goes, even though those that want to sell cedar claim it's the same thing.

There's a darn good reason that termites eat fresh pine but won't eat cedar until it's a decade or more old.

There's also a darn good reason the fungus that causes wood to rot immediately go to work on a pine board laying on the ground but do little to a cedar board.

The reason they use cedar inside saunas is that mildue is poisoned so it doesn't grow. Build a sauna from pine and the fungus and mildue will destory it very quickly.

No industry will admit the dangers of their products. Profit is all that counts.

The reason they use cedar is that cedar is essentially worthless as a structural material. It splits and is not as strong as pine.

As a result, much of the old growth forests in the western us is this substandard wood called cedar, and, because it isn't as useful as pine is for the construction industry, the lumber business heavily promotes this wood for other purposes.

Now, they are using this wood to make non structural products and the sellers are praising it as a wonderful long lasting material. Again, it's all about money.

The truth is that the building design is what makes a product last longer, not the type of wood.

If you will take the time to count the annual rings on some of the boards on bat houses and bird houses, you will quickly see these wild life products are made from old growth forests. What kind of conservation is that?

(20 to 40 years to add one inch thickness is old growth forest wood)


Gary Springer

[Gary Springer]

Thank you Frank