Very nice photos and at your site as well. Good luck with bat occupancy. The koi pond can't hurt in attracting bats although it is desirable to have larger bodies of water nearby. A general rule of thumb is if you have seen bats flying in your yard or nearby then your chances of attracting them to a bat house(s) is greatly increased. I went to a local apple orchard years ago and convinced them to have me put up some bat houses. According the bat house builder's handbook from BCI there was/is a 100 percent chance of attracting bats to properly designed bat houses which are placed in orchards due to the insects which forage there which are very appealing to big brown bats. I spent two nights at the orchard and did not see one bat. I never did attract bats to the two large nursery houses I placed in the middle of the orchard. Very disappointing indeed. The only water nearby was at the lower base of the orchard where there was a sizable pond and water area. Unfortunately it was likely contaminated from many years of pesticide spraying run-off since it was not a river and would only concentrate.
