Bat House Forum

[Terry Lobdell]

I've been thinking about starting this thread for awhile........I don't have a bunch of meticulously recorded data on this, just lots of observation of many bat houses over the past 10 years.........

I've always noticed here in NWPA there is a flurry of different bat box exploration/usage during the last 2 weeks in May......

Then in June they (mostly little browns) will pick a bat box and that's where they will stay for a couple weeks while pups are born.......

I say I've seen this with little browns mostly because big browns just seem to move around from box to box anyways throughout the season.........

It's almost like the little browns scout out different roosts before they give birth.........

Maybe big browns do the same but it's hard to tell because they move so much on a consistent basis........

Older established little brown maternity colonies that have never roosted in a bat box seem to be very leery of using a new bat box the first year it has been mounted..........

If several generations of bats in a maternity colony have used bat boxes for a few years then they will readily use a new box the first year it is mounted.........

I guess what I am wondering is do female bats scout for maternity roosts before they give birth?

[Charles Parker]

Terry,
my thoughts are that the bachelors scent the area and the females scout the area as familiar. In other words I think scent has a major role, not a fact - just my opinion. I am also always claiming that temperature plays as vital a role, I read that bats in the south (my area) use a very small number of available caves due to varying ventilation's and temps.

I agree on your comments about bats using a bat box readily accepting another vs a wall void. I see that in all sorts of wildlife as well. Raccoon's in Ohio use chimneys to birth in and down here in the south I have never seen it - yet my friend sees it all the time. I think its learned and I think bats would do the same.

As far as do the females scout, I do not know but we do know they fly together and leave the pups together when they fly out, so I would think it would be a group decision and again, I think it has to do with temps and scents.

[cloudman75]

I have also observed Little Browns often and up close for several years. I think that the pregnant females will use the same box they were born in
as long as it is acceptable. I have posted before that I think there is a dominant female which makes decisions on change. I have one here that I have posted about before and I call her big Mama because I think she is older than most of her colony due to her size. The Wisconsin DNR puts out a yearly behavior cycle
for Little and Big brown bats. The cycle states that they check out new roosts in Sept and OCt. Also this is the mating season. My Lbs. usually leave for a couple of weeks and return. I have a theory that they go to their cave area meet the males and breed. All of this is just a theory of mine, no facts to document. I had all my bats leave their favorite box once because I moved it during the winter. They did use it to have pups, then took the pups and left. I moved the box back to the previous year's location and the bats moved back in overnight and brought their pups.
My latest theory is that I don't know what these bats will do next. I moved the freetail bats favorite house and changed the location this year. The freetails came back, then left in a couple of days not to return this season. The large old 5 chamber is on a pole but strapped to a sweetgum tree with all the limbs near it removed and facing south. No bats have used it this year. I plan to put it back on the pole near its' old location next year. I sure hate loosing the freetails and pups they had each year.
I am convinced that before they leave this season for hibernation that they will have a bat box and location selected to have pups next spring. If something is not right due to the weather temp and so forth, they will make a decision to move once they get to that place. Like I have said before they do things all the time that surprises me.

Frank

[Charles Parker]

really interesting observations, thanks for sharing! I have not heard of the dominant female theory but its an interesting thought. Hey someone has to make decisions around there, lol

[Terry Lobdell]

Frank, I was not aware of that info from the Wisconsin DNR.........it makes sense they would scout out potential maternity roosts in the fall........

Bats are definitely attached to the exact roost where they were born or gave birth........I do move many of my boxes, often replacing them with a larger better box.......both little and big browns will readily use the new box if it is in the exact location as their old one.......

The old box I then place somewhere else in hopes that the scent within it will attract more bats.........However, now with the threat of wns here in PA I only move boxes locally never more than a couple miles away.....

[cloudman75]

Terry here is a link for the chart.

http://dnr.wi.gov/org/land/er/bats/bat_ ... _cycle.htm


Frank