Bat House Forum

[Richathome]

Nov. 29th and I never would have thouhght that I would see another bat until next year BUT sure as heck I found a bat in a single crevice house that I put underneath my back deck in May and have not seen an occupant in it until this afternoon. Nov 3rd was the last date for bats in my houses out back and I thought that would be the last of them. This certainly must be a big brown bat that has found this house under the back deck and protected from winds and against a poured concete wall that must provide some heat from inside the basement. I've read that big browns can tolerate cold weather. How can I tell that it is a big brown? They are hard to distinguish just looking up into a bat house. What telltale signs do I need to look for to tell it is a big brown bat? This bat does have a handsome brown color.

I ask this very question to Dr Joyce Hoffman Thanksgiving day after our annual dinner together. http://www.inhs.uiuc.edu/staff/index.ph ... me=hofmann I've been fortunate to know her the last few years thru my sister in law who went thru school with her and I've known she has done much with bats throughout her career. She explained to me the difficulty identifing the bats at a distance up in the boxes. Telling the species must be a learned talent that I need to develope.

I will daily keep careful watch on this new found friend and let you all know when it finally leaves its house. I was quite surprised to see it in the house this afternoon. It has been below freezing temperatures here in central Illinois the last couple weeks. These are hardy little fellows and makes me wonder how old it might possibly be.

(Joe, here I am again at the end of a post and I can't find spellcheck--Sorry) Rich.

[IowaNate]

Rich, most big browns have a wide nose, distinct black facial "mask", and are definately bigger than little browns. My big browns average about 1.5" wide when roosting whereas my little browns are usually less than 1.25" wide. But just given the time of the year I would be 90% sure that your occupant is a big brown.

[Richathome]

IowaNate, thank you for your comments on your big brown bats. I'm a learning novice and appreciate all information I can get. Early this morning I took another look into the house and with your info, a look at the pictures in my bat books and searching the net for more pictures I am reasonably certain it is a Big Brown, I also supppose all the little browns are in hibernation now. Late last fall I accidentally killed a bat that was clinging to the back of a 3x8ft piece of OSB board that I flopped down on the patio, that is what prompted me to build and place the single chamber house under our back deck. I went for a long walk in the snow after satisfing myself my new occupant was a Big Brown and couldn't wait to get back to try to take some pictures. Here are the pictures of an unusally placed bat house. If they want to use it early spring and late fall then I'll just leave it there.

Parden the streaming snowflakes but this is the location of the bat house under the deck. Last year the bats climbed behind the OSB boards leaning against the wall. The bat is in a much safer place now. The pokie dotted board under the house is an unpainted extended landing pad that I spray painted the staples that anchor the plastic mesh. The house is 22in.tall 24in.wide and bottom is 6ft 10in above ground and the bat seems to be OK with that.



Another view of the house, I left this picture a little larger so you could see my junk corner. Last year the OSB board was leaning where the house is now.



A look inside. Sorry for the glare off the mesh and bottom landing pad and the cob web also reflected the flash but that is the occupant there up above. What do you think IowaNate? Are we going to put a Big Brown sticker on this one? Also left this picture large for identification.


Another Look


IowaNate, I used a Kodak DX6440 zoom Digital Camera that my wife got me 3 or 4 years ago. I put it on auto with flash and just click away. My laptop accepts the card for easy loading and edit. Don't know if you've gotten a different camera but the digitals are great in my opinion.

Kerbat. Bernie, I use Photobucket as my picture host and I have a free account. Simply open yourself a free hosting account, then upload your pictures to Photobucket. When making a post you want to enter pictures just open Photobucket select your picture then I highlight the "IMG" under the picture and copy and paste to the post. It will appear as a code until you hit Preview. BE SURE to PREVIEW your post to make certain that your picture size is not to large. If it is just simply delete the picture code and resize it on Photobucket and reapply to the post. My first picture is sized to medium 320X240 and the other two are large 640X480. I hope this helps, I know you ask for this info eariler. Under the "HOW DO I" section Joe Spencer has links to Imageshack and Photobucket.

[IowaNate]

Excellent photo Rich! You can go ahead and slap a fat big brown sticker on that bat and there is no doubt in my mind.

I use a Kodak C813 which is 8.2 megapixels and it does really well for me, my wife got it for me last Christmas and I didn't anticipate the ability to record video with sound as well.

Here's a slightly blurry photo of my big browns taken in April of this year. You can definately see that your bat is the same species.

[Joe Spencer]

Great stuff guys! Rich, indeed little browns are in hibernation and as Nate says Big Browns can tolerate cold temperatures to a certain degree but not extreme cold for extensive periods for they then would have to raise their metabolism and burn precious fat. Biologists have placed Big Browns in freezers at or around 32 degrees to test their longevity and they surely are quite hardy and the bats lived for some time but some did not quite make it to spring due to these extreme tests. Yep as Nate said you do have a big brown bat there as your photo clearly identifies it. Little brown bats (often referred to as mouse eared bats) have shorter ears and as Nate said a much smaller nose not to mention their body size being smaller as well and the other characteristics that Nate mentioned. Thanks again for the great photos.

[Terry Lobdell]

Nice pictures! Rich, also notice the contrast between the light fur and the black face........often seems like big browns do have more of a contrast than little browns.......

[Richathome]

Thanks all for the identification of my Big Brown bat. IowaNate your picture was a super help to me for comparison, very nice picture. Now I believe that some of my late season occupants in my other bat houses were Big Browns. The tan body fur and dark mask visable when I looked into the houses and the larger appearing size on exit tells me they must have also been visiting Big Browns.

Now my main concern is the survival of this bat presently in torpor inside the bat house I pictured above since Nov 29th. If it remains there it will probably freeze over our winter with days of sub zero temps coming. Last year the bat that stayed behind the OSB boards disappeared but so far this one is staying put. Have any of you faced this situation? Any suggestions?

[#93]

I live in Cincinnati, OH it has been fairly cold here for some time. The average temp has been below freezing with several nights in the 20's. Last week I saw a bat flying around in my Dad's garage. It had been dark for about an hour and the bat was darting back and forth in several directions giving me the impression it was trying to find a way out. It was in the upper 20s at that time. I was very surprised to see one at all this time of year. I left the overhead door open so it could find a way out.

I was going to make a separate post but thought it would be appropriate to respond in this thread. Is it normal for a bat to stay in a climate like this or not freeze in the colder weather?

[cloudman75]

Hello 93
I live in N.W. Georgia, metro Atlanta area. We had a few nights in the mid 20s recently. All my bats left, even the one that usually stays in my attic louver in winter. A couple of days ago we had rain and temps in the mid 60s. That night I shined a light in my bat houses and in the larger one there were 3 bats. They were smaller than little browns, but looked very much like L.B.s I don't know what is normal ,but this year with bats is certainly unusual. Tonight it is mid 20s and all the bats have gone again. Where they go and how they survive burning all that energy is beyond me. I viewed your PVC bat house and it
surely should be used by bats looking for a good home is my opinion. I really liked the pvc spacers you used between the baffles. I am converting an old garbage bag holder to a bat house and may use your idea for spacers between the baffles.
I know from now on I will be using Nate's tool for grooving wood baffles and not the screen and staples I have previously used.

Frank

[Richathome]

A few days ago I realized my Big Brown bat needed to find a warmer place to hibernate to survive our cold winter but he didn't move during our last short warm spell so I took some action after reading a post by USVI Wildlife "Bat House Project Questions" about monitoring bat house temperatures and Joe Spencers response about thermometers.
This is what I bought to monitor my bat house temperatures over the winter. Indoor Outdoor Thermometer with temp probe about 30 inches long.


I mounted the thermometer to a 1x5/8 inch by 36 inch long strip of wood and extended the probe to the end of the strip and then inserted it to the inside top of the house like this. The bat is roosting at top left and probe is at top right.


Next step was to fix a 13 foot piece of heat tape to a 24 by 24 inch piece of 1/4 inch aluminum plate. 7 loops across the face of the plate covered it well. Then some fiber glass insulation and some boards to hold it in place. This is it below, is my wife ever going to like this!! Emergency until spring I'll tell her.


The electrical heat tape has a pre set thermostat set at 38.5 degrees and I have it slightly tucked in under the insulation and the temp has been consistantly holding at 40 degrees for 24 hours and our outside temp has been 5 to 12 degrees the last 24 hours. The Blue outside scale is the probe in the house and Red is actually reading the outside air temp.


Hopefully this Big Brown bat will survive the winter. 40 degrees seems OK but I imagine bats in caves may have temps around 50 Degrees. Any expert advice or thoughts about my meddeling with Mother Nature.

[cloudman75]

We had 67 degrees today and low in the 50s. My 3 small bats have returned to the bat house tonight. We expect mid 60s and a couple of 70s this week so I guess they can forecast weather temps. What ever they are they evidently stay active on warm days. They always leave and go somewhere else when it gets below freezing. I have not yet identified what they are. All my little browns are in hibernation. These are about 2/3 size of little browns.
Big browns from what I have read can take the cold better than most. It appears your bat has made up its mind to stay at your house. It is lucky to have a friend like you to provide some comfort. If you disturb it too much it may
leave so good luck with your temperature observations, but go easy.

[Joe Spencer]

Hopefully this Big Brown bat will survive the winter. 40 degrees seems OK but I imagine bats in caves may have temps around 50 Degrees. Any expert advice or thoughts about my meddeling with Mother Nature.

Awesome work Rich! Looking forward to your data logging and feedback on your occupant. Based on below, your temperature may just be good enough. The only thing that we can't provide and must consider is the natural amount of humidity that exists in caves and mines which assists in keeping bats hydrated during their hibernation. But since big brown's often hibernate in buildings/homes they may tolerate less humidity than other species which may need more.

Excerpt from URL below Big brown bats hibernate in cold sites just inside cave entrances (coldest area of cave).
http://mdc.mo.gov/nathis/mammals/batfacts/

Excerpt from URL below: Ideal hibernating temperature for many insectivorous bats is: 45 degrees F.

http://www.batcon.org/index.php/education/article-and-information/bats-magazine.html?task=viewArticle&magArticleID=950

QUESTION FOR YA: Is the interior space on the other side of the concrete an insulated room or non insulated? If non insulated it might explain the transference of extra warmth inside the bat house. Had this bat house been mounted on exterior siding your occupant would likely have left.

Rich, as for your spell check question? IF you don't already know, when you type a word in the post box then hit the space bar for the next word the the word you just spelled will have a red underline telling it has been miss spelled. All you need to do is Right Click the word and select the proper spelling from the choices it gives and it will automatically change it.

[Richathome]

Cloudman75:
Glad to here your bats come and go at different temperature ranges. I do believe they know what they are doing. Its good to have a little mystery with your bats, they definately do not make it easy for us to identify them. That drives us to learn more and more about them and one of these days you will find the answer to your mysterous visitors.

Joe:
Thanks for those links. I have read them well and have searched for more. I've found that the Big Browns should do just fine between 38 and 42 degrees which is where the temperature has been holding the last 3 days with our outside temps rangeing 5 to 32 degrees and we are expecting zero temps this weekend. One study I read said they held Big Browns at 39 to 41 degrees from the middle of Nov after the bats went into hibernation until May with no ill effects. Another study held them in the hibernation state for 300 days but they were supplied with a water source. Perhaps I'll provide some water somehow.

The poured concrete wall is a finished room on the inside but there must be some heat coming through to the outside which is most likely why I've had one or two bats stay behind the OSB boards the last 2 late fall seasons for a while then dissapear. This bat didn't find this single chamber house by chance I don't believe. With them living towards 20 years I do believe this bat has been here in years past and found the house comfortable enough to stay. Looks like I'm commited to keep it at a safe temperature for the rest of the winter.

About the spell check, I am using IE browser and I see no indication of mispelled words even intentionally mispelling them. I also have Firefox as a browser--would it work on that, I think spellcheck only worked on IE before the change.

[Joe Spencer]

Rich, my mistake and thanks for the feedback for clarification. I have been using Firefox which I prefer and it is Firefox which has the built in spell checker which works in the compose box. Internet Explorer does not. I prefer Firefox over I.E. Currently our new forum software does not have it built into the compose box but there may be a modification I can add in the future. Looking forward to your big brown hopefully staying the winter. A few years ago I was going to artificially heat a bat house in hopes of them staying over but I never got around to it. Glad you have. Big Brown Bats mate sporadically from November through March but most mating occurs in late fall so I would think your bat should hopefully be staying. Do you have power back up (generator) if you were to lose power or battery and inverter to continue heat to the bat house? We just lost power for 5 days due to a horrible ice storm bringing down trees here in Massachusetts as seen on my street below. Luckily I put our first wood stove in our house this fall and we were fine:



My underground utility pole is on left but look how the ice weighted down the lines going to the street:

[Richathome]

It looks like my Big Brown Bat has survived this last brutal cold spell. Thursday the low temperature here was -17F and yesterday a low of -21F. I realized the cold blast was coming so I exposed the regulating device on the electric heat tape completely to the outside air temps and the temperature remained fairly constant around 40 degrees but it did get up towards 50 degrees for a short time, so the Big Brown moved to the lower third of the single chamber house. It must have gotten a little warm for it so it moved. Good evidence that it was alive and well so far this winter. This is the third time I noticed the bat change location in the house this winter. I look for it to move back to the very top left of the house since the temperature has again stabilized to 40 degrees inside the house. I check the temperature at least twice a day and I'm happy to see the bat is still alive and well. Hopefully it will make the winter.

Joe your pictures of your ice storm were something to behold. The ice can be very devastating as I experienced here in central Illinois. I lost many limbs from 2 very large white pines in our back yard. Mother Nature has a way that continues to amaze me.

I'll keep a constant watch on my hibernating Big Brown until our spring thaw. They certainly must be a tough critter.