Bat House Forum

[kent borcherding]

terry ,

If you are having variations of ambient temperatures bats will move around to different bat houses.

I have found in early spring and late fall bats definitely prefer the Oregon wedge bat houses. The oregon wedge houses are 2-4 ft wide - 26- 36 inches in heigth , and the sides taper from 1 1/2" at the bottom to 1/2" at the top. single chambered

I have about 9 different styles and designs at various sites and the Oregon wedges are always full early spring and late fall. Bats second choice early spring and fall is the single chambered rocket boxes.

presently I monitor 104 bat houses inhabited approx 12 ,000 bats 3 species. big and little bowns and northern long - eared .

Always looking for a new idea or design to experiment with , firm believer in we still have much to learn about building bat houses.

You can construct the slanted baffle bat house with removable baffles and easily slide a new set of baffles in the houses every coulpe of years.

Cal Butchkoski was doing this with the Penn. state 5 baffle houses approx. 10 years ago. I think it is a great idea , because you still use the same sides , back & front , roof. Also the odor from the colony that used the bat house will remain.

[Joe Spencer]

Good news! I forgot Terry, do you have more little browns than big browns in your houses?  Thanks for the feedback...

[Terry Lobdell]

Joe, Here at my home I do have more little browns than big browns. So far this year it appears like I have 15-16 big brown mothers for the 4th year in a row. My little browns increase in numbers slightly each year. I have at least 40 maybe 50 little brown mothers this year. I have not done exit counts at other locations yet. 

[Terry Lobdell]

Kent, would the Oregon wedge house be more wasp proof having the 1/2" crevice width at the top?

And do your big browns differ from little browns in their preference for certain houses?

[Joe Spencer]

I'll await Kent's reply but one would think so.   Since the oregon wedge design is a single chamber I'd consider placing multiple single OWedge houses together (horizontal stack) to create a nice large house with greater thermal mass for mounting on poles/posts.  Placing a  bottom piece on the sides would allow you to stack and secure each piece/house separately for lightweight easy mounting.  I'm finding it fascinating that Kent's feedback is showing preferences for these houses early and late in the season.  If it is a nursery colony is there a connection between pup rearing and design or is this in season preference applicable to bachelors as well? 

[kent borcherding]

Terry ,

Big browns sure prefer the bat houses with the 2" inner roofs , better internal temp control .

Will try and post some pics of photos of large groups of bat houses that have been able to hold big browns in for the last 10 - 12 years. I have a Mac computer sometimes get confused or difficult to post photos.

Wasps usually a problem in any bat house except the Rubicon material , wasps nest will not adhere to Rubicon.

Most of my houses are mounted in groups and I will usually place a small 3 baffle house with wide spaces between the baffles , wasps will prefer this house to build the wasps nest in .Very few wasps nest in the other houses in the group .


Another solution for 2 houses mounted back to back is make the first baffle at the back 1 1/2" and wasps will build there nest in that baffle .

Concerning the slanted baffle houses will be making some with screen on the back instead of a wood back. Bats like to hang on vent screens.

[Terry Lobdell]

Thanks Kent and Joe,  I'm wondering if maybe I should use rubicon for ceilings in bat houses? Even if some wasps build nests in the sides or on the baffles seems like they would be easier to knock out?

[Terry Lobdell]

Here are the two bats that are almost always roosting tight together either in east or south facing bat houses on my home. I did see them on the west side once. I think I've seen them in about 4 different bat houses so far.......I guess they are just little browns now that I've got a closer look. I figured it would be big browns that would first use this house given that it faces east..........my prediction is come a late July hot humid spell I will have a bunch of big browns roosting here!

[IowaNate]

 Great photo Terry! I am glad to see your slanted baffle design has occupants. And I am looking forward to how both of your bat species react to this house.

[Joe Spencer]

Nice Terry!  Does the angled baffle house make photographing easier than a vertical partitioned house?  Hmm the bat chose an upper chamber.  I'm wondering since they're angled if this design slightly creates a partial multiple internal roof situation resulting in a slightly different environment. :cool:

[Terry Lobdell]

Thanks, Nate & Joe! I think this design does make it easier to take pictures.

There probably is a temperature variation in each crevice. This pair was in the same location on 2 different days. The bats can move from crevice to crevice internally.

The top part of this house is fairly tight, so I think it will stay warm at night even with the open vent style front. I didn't drill any holes in the sides for ventilation. The two one by fives which make up the sides have a slight crack between which should provide some ventilation. I will watch this house carefully to see if weather conditions affect usage. That's one thing nice about having bat houses mounted over your back deck.........all you have to do is step out and take a look!

[Terry Lobdell]

On the night of 6/16/08 I must have had investigation from big browns of this house because there was a lot of guano underneath. However, the next evening I shined a light up and there were no bats roosting........they must have been just checking it out.......Judging by the amount of guano it had to have been the mothers......

[Terry Lobdell]

My big brown maternity is now using this house. A couple nights ago I had around 10 mothers with pups up in it. This big brown maternity has now used 8 different houses this year!  Seven mounted on my home and one mounted on a pole. So as in past years they are still showing strong preference for bat houses mounted on a building.