Bat House Forum

[IowaNate]

  I am heading up to Abel Island this weekend where thousands of little brown bats have made thier home. It's a private island on the Mississippi River that my fiance's parent have a cottage on, and they are in dire need of more bat houses. Luckily my fiance's mother is on the island's board of directors and she is making a case for a few bat houses to be hung in the common areas of the island. Most of the boat garages have hundreds of bats along with many of the cottages. I have only seen three bat houses on the island and they are packed full to the point of bats almost hanging out of the bottom! This is the place where I have seen a house hung on a tree in a mostly shaded location, but with a nursery colony of about 200 bats. I can't imagine what a large bat house mounted in a better location might bring.

  This weekend will be spent looking for good areas to hang bat houses and writing up the locations to give to the board. In addition there is gonna be alot of fishing, relaxation, good food, and a few beers by the fire with the family!

[Terry Lobdell]

Nate, that sounds like an amazing location! It's too bad I'm so far away because I have a lot of lumber I could donate to  you for bat houses there. That might be a good area to get boy scouts or some other group involved. It will be exciting to hear how your projects turn out there! 

[IowaNate]

  The idea of bat houses wasn't taken with too much positive attitude by the other islanders. A few of the cottages are actually infested with bats, and there isn't a way to keep them out unless the building is demolished and rebuilt. But, three people did want a bat house from me to put on their property and I am putting one at our cottage. So there will be four more bat houses on the island by Summer's end.

[IowaNate]

 I observed bats roosting in all sorts of unusual places. Almost every shutter mounted on a building had bats behind them, even the fake plastic ones mounted on vinyl or aluminum siding. One boat house was made aluminum siding and roof but the bats still found a way to cling to the slick surface long enough to climb into the slots in the corrugated metal roof, although they usually made two or three attempts. In three separate locations I found bats roosting no more than 7 feet from the ground underneath elevated decks or behind stairs.

 The three existing bat houses that I found were all mounted on trees. One was an older BCI nursery model with four chambers. It was painted medium gray, mounted 14 feet up facing South, and received about 4 hours of direct sunlight. This house had a very large colony of at least 200 bats.

  The second house was of the older Johnson design (box shaped with 6 - 1" chambers that ran front to back). It was unpainted, mounted 12 feet up facing East, and received about 5 hours of direct sunlight. The house was in very poor shape with the roof making a 1/2" gap at the back of every chamber, but it still had 3 bats when I checked it (along with many wasps and their nests).

  The third house was a single chamber design about 14" wide and 20" tall. It was painted medium brown, mounted about 10 feet up facing Southeast, and received about 6 hours of direct sunlight. It had at least 2 dozen bats in it.

  The bat houses that I am putting on the island should provide better roosting options for the bats, but it seems that they are not very picky when it comes to the currently available roosts.