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Joe Spencer
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| Joined: | Mon Feb 11th, 2002 |
| Location: | Massachusetts USA |
| Posts: | 529 |
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Posted: Wed Oct 10th, 2007 08:33 pm |
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These are slanted baffle bat houses that were used by big browns summer
2007.
Trying some designs should help keep pups from falling from boxes .
thanks ,
kent
After observing numerous bats liking shutters over the years I'll look forward to Kent's experimentation with these!
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IowaNate
Member
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Posted: Sun Nov 18th, 2007 08:02 pm |
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I am also very intrigued by this design. I have had big brown bats roost in my gable vents which offer only about 3 inches of roosting space before the screen on the interior. These houses seem to have about 6" of roosting depth. My main question would be the variation in temperature in each roost partition. Perhaps a much deeper house could be constructed (12"+). I will be watching this post closely!
Happy bat housing!!!
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Terry Lobdell
Member
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Posted: Mon Nov 19th, 2007 05:20 am |
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| Last year I observed 50+ little browns roosting behind the louvers of a gable vent. This design would work very well with rough sawn lumber for the baffles. It would be easy to construct as well. I want to try some with different angles for the baffles. I think there could be many variations to this design that would be effective.
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Joe Spencer
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| Joined: | Mon Feb 11th, 2002 |
| Location: | Massachusetts USA |
| Posts: | 529 |
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Posted: Fri Nov 23rd, 2007 06:11 pm |
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In addition to the merits of this design in helping prevent Pups from falling from bat houses, I'm posting this excerpt below in this thread to see if there is some sort of possible connection between certain species of bats' potential preference for horizontal roosting during diurnal roosting, daily torpor or hibernation:
Most studies of the thermoregulatory ecology of bats have been limited to laboratory experiments or studies of individuals roosting in artificial structures. We investigated the interaction between thermoregulatory behaviour and roost choice in reproductive female Western Long-Eared Bats, Myotis evotis (H. Allen), roosting solitarily in natural rock crevices. The study was conducted in the badlands of the South Saskatchewan River Valley, Alberta, Canada, during 1997 and 1998. > Individuals used torpor every day and the amount of time spent in torpor was primarily influenced by the amount of time available to do so. Minimum body temperature was influenced by ambient temperature, although the form of this relationship differed between pregnant and lactating females. Pregnant females used deep torpor more frequently than lactating females. All individuals roosted in rock crevices but pregnant and lactating females chose roosts that were different in structure and thermal characteristics. Pregnant females chose horizontal roosts that cooled at night but warmed quickly during the day, thus allowing passive rewarming from torpor. Lactating females chose vertical roosts that stayed warm at night when non-volant pups were present, thereby minimizing thermoregulatory costs to the young.
Maybe slanted roosting offers a potential compromise between the two positions vertical/horizontal which may appeal to bats and why they're so often found in gable end attic vents with screen on the other side preventing attic access yet still quite content enough for bats although they're seemingly overexposed?
Is it possible that when bats are in torpor/hibernation and not defacating, they could prefer a slanted/horizontal roost so as to be less taxing on burning fat reserves? When in a highly active state (feeding, defacating, nursing etc.) the vertical position is preferred? I noticed two of my last Big Browns choosing to roost on a wooden spacer in the front area of their body while totally vertical due to the design. Were they doing anything possible to lessen the burning of precious fat reserves?
Maybe it is worth experimenting with a bat house that is mounted on a building, heated with a thermostat to emulate hibernacula temps. and also providing horizontal surfaces in attic compartments to have them stay year round in colder areas such as the upper US and Canada? Insertion of a video camera (cheap black and white camera) would confirm bat hibernacula occupancy.
All of the latter is merely speculative by me but there seems to be some evidence for this horizontal roosting during hibernation if other criteria is met. Maybe it merits experimentation to keep bats year round in their diurnal feeding roosts (bat houses). With this slant, there would be no need for time consuming saw kerfs. Rough lumber with the proper degreed slant would provide suitable non-taxing gripping. Nate, I concurr with experimenting with a deeper design however, the only concern would be potential urine and feces buildup which could lead to a slight increase in parasitic activity. Multiple roosts would help lower that. What about keeping a slight gap between the rear wall and the slants allowing bats to move and change/select any slant without exposing themselves in the front? Hmm I suppose the latter could cause heat trapping to be lost to the upper attic. I'd put some Pet Screening on the inner vertical plywood back for gripping which would be the only piece needed if backing is plywood. Nate, I too am intrigued by the possibilites of this design. Time to get experimenting!
Appreciate your insight and feedback.... Joe
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KC5TPA
Member
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Posted: Fri Nov 23rd, 2007 11:52 pm |
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| Hmmm... I was going to look at experimenting with heating a house this weekend and now I have found this so I'm wondering how I could incorporate both.
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IowaNate
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Posted: Sat Nov 24th, 2007 05:17 pm |
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Joe, I have observed some things that might add support to the horizontal hibernation. My nieghbor's house has held hibernating big browns for many years now, recently the house was renovated and new tenants moved in (hence perhaps the increased late season occupancy in my bat house. But during the last three years when the family next door got into the attic crawl space (temps around 40 degrees) to get Christmas decorations they found big browns. They always came over to get me since I am the "Batguy" of the neighborhood. Of the 5 big browns that I observed, all were laying on the floor of the crawl space perfectly horizontal. As you know, I am already in the midst of building a few houses that incorporate the standard vertical chambers with 14 additional 45 degree chambers.
Happy bat housing!
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KC5TPA
Member
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Posted: Sat Nov 24th, 2007 05:25 pm |
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| Do you have pics of these houses you're working on?
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IowaNate
Member
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Posted: Sat Nov 24th, 2007 05:38 pm |
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Here is the basic design. Overall the house will be 21" tall (24" with the landing pad) and 20" wide. The dark blue area between the two different house styles will be a "crossover" slot. I am going to make a few of the houses and put them on my home where the big browns are currently roosting in occupied houses. I should be able to get the first two finished in a few days with pics of the finished design. Any ideas or insite will be greatly appreciated!
 Last edited on Sat Nov 24th, 2007 05:59 pm by IowaNate
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Terry Lobdell
Member
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Posted: Sat Nov 24th, 2007 06:22 pm |
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Nate, that is a good design! It gives the bats a lot of roosting options.
On the subject of horizontal roosting, I have observed little browns (most likely bachelors) roosting inside of lumber piles being air-dried (with one inch spacers between each layer of boards.)
My guess is they like the thermal storage a large lumber pile provides as well as the air circulation.
I have seen the bats laying horizontal and the guano as well.
This fall I stacked many piles of lumber here at my residence for air drying. I am going to be checking it next summer for bats roosting in the spaces between the boards.
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IowaNate
Member
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Posted: Sun Nov 25th, 2007 01:57 am |
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Here's the current work in progress. I don't have any of the slanted baffles in yet, but the standard vertical partition part is done (minus the roof). The overall dimensions are 22" wide and 24" tall. The standard house is 12" wide (inside dimensions) with 18" tall partitions. Each of the 14 slanted baffles will be 6" long and 8" wide. In the bottom photo you can see the access from the main house (rear chamber) to the slanted baffles. I have yet to get big browns to form maternity colonies in any of my bat houses, perhaps this dual design will entice them to. This design will eventually replace the house that my big browns are using for summer roosts and currently "hibernation???"
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KC5TPA
Member
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Posted: Sun Nov 25th, 2007 04:09 am |
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I see you have only scored the plywood at the 'crossover' point. Do you plan on holding only the slats in this area away from the back or will there be access 'behind' all of the angled slats?
I thought of in interesting design like nothing I have seen yet, but incorporates the pluses of many other designs, not to say it will be without negatives, but I don't know how long it will take me to 'gather' what I need to make it happen, but I have a renewed drive since my bats have returned.
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IowaNate
Member
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Posted: Sun Nov 25th, 2007 04:15 am |
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I am only planning on an access to four or five angle baffles from the main house. the angled slats will have notches in them next to the slot. I MIGHT put a slot in the side of all the angled baffels so the bats can move up and down through all of them. Although I am building at least two of these houses so I can experiement a bit. Thanks for the interest KC5TPA!! By the way, this house is built with 1/2" plywood instead of my usual 1/4". I did this to help with heat retention and temperature buffering, and the weight of the house won't be too much of a problem since I have easy access to the side of my home where they are getting installed.
I would like to see more people experiment with designs that might promote hibernation in latitudes North of 38*. I think that designs that are mounted on buildings to stabilize temperature fluctuations, perhaps with slanted or horizonted baffles might just be a key facter.
Last edited on Sun Nov 25th, 2007 07:03 pm by IowaNate
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IowaNate
Member
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Posted: Sun Nov 25th, 2007 10:34 pm |
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Here's the finished house (minus paint). Note the 7/8"x 2" slot in the slanted baffles (second photo), this slot goes through the lower 4 baffles and from the photos in my above post, allows bats to access the rear chamber of the standard vertical house.
The slanted baffles are not attached in any way to the house other than friction, I think this is a plus if I want to pull the baffles and make the small slot continue through all of the baffles (I am not worried about them falling out or shifting as it took a good amount of force to slide them between the spacers). I haven't put a horizontal vent slot in the front chamber yet. I can forsee wasps using the bottom of the slanted baffle area, but perhaps it will be used by my big browns on extra hot days, providing a semi-sheltered cooler area. This house provides so many options, only time will tell how the bats choose to use it!
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KC5TPA
Member
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Posted: Sun Nov 25th, 2007 10:43 pm |
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| Very interesting, very curious about the horizontal slats. I am intrigued to see how this is utilized. I wish you could incorporate a camera to see if the 'crossover' is used as your design intended.
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KC5TPA
Member
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Posted: Sun Nov 25th, 2007 10:46 pm |
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I noticed on another thread you started you were involving your children, very commendable by the way, so I thought you might like showing them my videos from earlier this year.
http://www.youtube.com/kc5tpa
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