Bat House Forum

[IowaNate]

 We have had a few days in the mid 50's lately, and I decided to check my bat houses that are mounted on my home after work tonight. My Northwest house has three big browns, and my South house has one big brown!! I have not seen any insects flying yet though. My problem is that I was going to replace the Northwestern house this spring, and now it is already occupied.

   My colony between all three houses mounted on my home has been up to 9 big browns last year. I am still going to replace this house when I can find a time when the bats are gone. I never expected them to return this early in the season. But I am very glad that these four made it through the winter ok, and hopefully more will arrive soon!

[IowaNate]

 Here's a photo of the Northwest bat house taken on March 24th showing the three bats. Sorry about the poor quality, but you can easily make out the bats in the photo.

[IowaNate]

 I am hoping that with the new larger houses that I will be mounting will encourage a nursery colony of big browns. Being exactly 1/4 mile from a trout stream, I feel that I have a good chance. For the first four years that these houses have been hung I only had about four bats total, then last fall of '07 (early winter) I had nine bats total. My new design of the standard bat house with the addition of slanted baffles will be hung on the South side of my home this week. I will be checking this new design on a daily basis to see if it is occupied. The photo of this house was before I painted it dark brown.

[Joe Spencer]

Gosh that is good news but agreed can't wait to see how the shutter/hybrid style houses perform when you have them up.  No whitenose fungus in your bats and hopefully area ever.  Thanks for the update Nate! :thumbsup1:

[IowaNate]

 The white nose fungus/syndrome hasn't affected Iowa yet as far as I know. But we need to know what is causing this affliction.  This "disease" needs more research before it spreads even more. I don't even want to think about our Indiana myotis being depleted due to this unknown malady.

  I am worried most about the fact that we don't know if the fungus is the cause of death or just a symptom of a much larger problem caused by some other unknown factor. Some people call me a bit extreme and wierd due to the fact that I have so much passion for bats (and wildlife in general) but I want to do my part to help solve this problem of hibernating bats dying before it spreads to my area and to save as many bats as possible in the areas that are already affected.

  I routinely monitor John Chenger's forum as well, and there is alot of info there and some more people trying to find the cause and stop the spread of the bats' deaths. Donating just $1 and multiplied by a few hundred people could fund a person to do some research and perhaps solve this. We all have at least one dollar that can be spent to research this!

[IowaNate]

 It's now March 30th and the there are 5 big browns total in my houses. One of them is a VERY large individual. I have never seen a bat in Iowa that was this large up close (Hoary bat is our largest species with a massive 16" wingspan) but it is most certainly a big brown. It is in a 7/8" chamber and the bat was about 1.75" wide and 3.5" long while it was huddled up tight. It was close to the bottom of the house today so I could get good measurements without disturbing the bat. The temperature today climbed to 58 degrees. And the Northeastern facing house still has the biggest number of 4 bats at this time.

  It seems like this house goes against most reccomendations for being successful as it gets a minimal amount of sunlight and is facing North, yet it has been occupied since the first week it was hung and the occupancy has increased by at least one bat per year. Then again these are bachelor big browns which do prefer cooler roosting temps. But I had no idea they would roost in these numbers together.

[Terry Lobdell]

Well said about white nose fungus Nate............on the subject of big browns tonight (March 30th) I had one roosting in a west facing house............This house has had suprisingly high usage given it's western orientation. I believe due to heavy construction and some insulation........this is in agreement with Kent's theory of bats preferring this type of construction because heavier wood holds night time temps better. And big browns certainly seem to like stable temps.

 

[IowaNate]

 There are now six bats total, five in the NW house and one in the SE house. I just put up the slanted baffle/standard baffle house up today on the South side of my home. I managed to mount it 15 feet 8 inches from the ground.

 The bats might actually hunt for insects tonight as the daytime temperature reached 65, so we shall see if a few of them move into the new house. All of my big browns are currently roosting in the rear chamber of the bat houses, and the chambers measure 7/8".

  All of the bats seem fat and healthy, and three of them graced me with open eyes and a freindly chatter (ok, they were probably just upset that I woke them up).

   Happy bat housing!

                                       Nate

[Terry Lobdell]

That is great news Nate! I am now up to 5 big browns total. This time last year I had approx. 10 but it's been colder this spring so I'm guessing that is the reason........

[IowaNate]

 Here is the photo of the new bat house design. And yes, I accidentally picked up semi-gloss laquer instead of flat over the brown paint (hence the reflective appearance). Hopefully it will still absorb plenty of sunlight, my old pickup truck was brown and shiney and it got hot as heck even with a reflective windshield cover! As of today 4/07/08 there are still no bats using this house, but then again it has only been one night and the temps dipped down to upper 30's last night.

[IowaNate]

 7 bats now, still no use of the new slanted baffle hybrid house or the NE house. 6 of the bats are in the NW house and 1 is in the SE house. Temperatures have taken a nose-dive lately and not been over 50 degrees, but next week is forcasted for upper 60's.

  I will definately be paying more attention to the bat numbers this spring and summer since the are 4 house options with a wide range of temperatures that could entice a few nursing mothers.

    Terry, how many mothers do your big brown nurseries usually have? I hope that my numbers increase substantially this year even if they are all males and non-nursing females.

[Terry Lobdell]

Nate, the big brown maternity at my residence has stayed at 15-16 mothers the last 3 years. My uncle has a big brown maternity that I'm guessing has between 30 - 50 mothers. I hope to observe his colony more this year to get a more accurate count. He is much closer to multiple sources of fresh water. His location has potential to attract a lot more bats. I wish I had time to mount more houses there!

[Joe Spencer]

[b]

  It seems like this house goes against most recomendations for being successful as it gets a minimal amount of sunlight and is facing North, yet it has been occupied since the first week it was hung and the occupancy has increased by at least one bat per year. Then again these are bachelor big browns which do prefer cooler roosting temps. But I had no idea they would roost in these numbers together.

Nate, I believe you are correct.  Since big browns are quite hardy when it comes to the cold,  they may in fact prefer cooler temps at this time of the year for the main reason of being able to more easily/readily enter a non-taxing daily state of torpor.  If insects are not active, cooler locations allow for continued fat preservation especially for males which don't need to raise their internal temperature to nurture young during the gestation period which is often still quite cool seasonally in many locations.  This looks like a set of bachelors which are just waiting for warmer temps to arrive for increased activity and foraging.  Just a hunch I have after witnessing similar behavior and preferences for Big Brown Bachelors over the years.  The shutter baffle hybrid house looks great and we'll look forward to the updates on it!

[IowaNate]

  Here's a satellite image of my neighborhood. My house is the red box on the far right of the image and I dotted the trout stream to show it's location more clearly. My neighbor (brown roofed house to the South) has more bats making it into his living space this week, and he is hearing them in his walls. They use his house for hibernation every year, but I don't think they use his house much (if at all) during the warmer months. 

                  

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[Terry Lobdell]

Nate and Joe, your theory of big browns preferring to roost in cooler locations during cold weather in the spring may explain why my big browns are mostly all in my  insulated west facing bat house. I did hear them chattering tonight at 6pm once afternoon sun warmed the house but the lack of guano indicates they have not been feeding. Nights here have been in the high 30's. They have been roosting in the back crevice which would stay the coolest. Very interesting!