Bat House Forum

[Canute]

I built the bat houses pictured and installed them on June 20th and my fiance and I first noticed occupants on July 25th. We were/are absolutely thrilled to see bats so quickly! There were three bats, one in the left house and two in the right, and they have been consistently present since then. They seem to be quite attached to their new home! Occasionially we only have two as one seems to have other roosting locations. I was expecting the presence of the first few bats to draw others in, however the number has not grown. I'm curious...Is it typical for houses to populate one bat at a time or do they normally come in "flocks"? (or whatever bat groups are called). As far as my building and location specs: Both houses are four chambered houses built to specs from BCI. (other than I expanded a 3 chamber plan to a 4 chamber) Exterior is painted with a raw interior. All baffles are scored every 1/4" and the landing pad and rear wall has black plastic mesh. Baffles are all 7/8" apart. We have a large open field directly in front of the houses with a pond approximately 30' in diameter about 60' from the bat houses. Prior to placing the houses we could typically count 3 to 5 individuals flying over the field on any given night. The two down sides are: First I was unable to place the houses in the middle of the field so they are located back against the treeline however they were strategically placed specifically to receive direct sun from sun-up to approximately 2 hours before sunset. Second is the fact that they are only about 8' off the ground which I did based upon lumber availability and the fact that I had seen pictures of a bat conservationist hanging several houses side-by-side no more that six feet off the ground and figured he knew what he was doing. So I'm wondering...should I consider the nearly immediate presence of three permanent residents to be a good sign of things to come? Or should I be concerned about my design/placement due to the fact that no more have decided to move in over the past few weeks? Also we have noticed that there is ALWAYS one bat in the left box and two in the right (NEVER the other way around). I have read some articles on little brown bats that suggest this may be a division of male versus female. Any thoughts on that? I'm also curious to know if anyone can tell me during what months we might anticipate occupancy (we live in central coastal California - Santa Cruz, though our specific area maintains more inland temperatures)? And Is it possible to receive more than one species of bat in a single bat house? (little and large browns for instance) Anyhow, my fiance and I are very much enjoying the whole bat house experience and appreciate any info given.

[Terry Lobdell]

Nice looking bat houses! I live in NWPA, so I can't tell you much about CA bats. In my area that is unusual to get occupancy so quick........however, this is the time of year my bats explore the most........both big and little browns.........And yes your quick occupancy is a sign of more success to come!

Yes different species will roost in the same box, however, I have never seen a maternity colony of big and little browns in the same box at the same time..........I have seen one or two little brown bachelors in with a big brown maternity and visa versa. Little brown and big brown mothers have vastly different roosting needs while raising their pups.........some of other posts on here go into more detail on it.........

I can tell you at most sites where I mount boxes, my little brown bats seem to increase in number each year.........however, I am about 200 miles from known WNS infected hibernaculums so I fear the worst in a year or two..........I am praying for a miracle though.........

[IowaNate]

Congratulations on the early success! And the fact that they are staying in the houses shows great promise for the future.
The height shows that bats will roost in houses lower than most reccomendations, but placing them higher without sacrificing sun exposure never hurts.
Being this late in the season it is difficult to tell whether or not you will get a nursery colony next year. But next year is when you can really see what the bats preferences are if they come back (which is likely). I would keep close eye on the houses next year to see how the bats move and what chambers they seem to frequent the most. Given the good photo of the bat using your house I will make one reccomendation. If the other bats are about the same size and you are considering putting up another house or two, try keeping the partitions at 3/4". My little brown bats seem to prefer spaces when their belly and back can touch both sides of the roost without "puffing up" too much, perhaps to wedge themselves without fear of loosing their grip.

Good luck!

[LarryH]

I was also very lucky to get bats into my new houses very quickly years ago when I first put them up, but I put up my houses in March. We had bats roosting in a nearby barn that was falling into disrepair, and they seemed anxious to move into our “modern” houses. I only had a handful of bats the first year, but it has steadily increased every year and we now have several hundred.

Two years ago, I put up a separate “nursery” house on the end of the hay barn, and it attracted a number of little brown bats with their babies. Both last year and this year, it had bats in it from early June until mid-July, and stays pretty much empty the rest of the time. They don’t seem to like it as well as the houses up on the pole. It may be because it is only about 14’ off the ground, and the ones on the pole are 20’ off the ground. Or, it may be because it is on the side of a metal building. Not sure.