Bat House Forum

[kerbat]

Yuk, my rocket population continues to very very volatile!

3 nights ago, no frogs but bats were down from low of 140's to 70. Missed two nights of inventory, but this morning there was no activity around house except for 3 lonely bats. Finally one did enter thru the vent slot. Climbed up and looked in and can not see anything wrong in box or on the landing ramps.

Agreed that I had been changing some things on pole, but nothing I would call drastic. "ENEMY OF GOOD IS BETTER" Had replaced the plate predator guard with the wrap around aluminum one. Thought it was good since while I was on the pole on the ladder, the relection off the plate was pretty fierce. Sorry Layla, I did grease the top 4 inches of the wrap around to discourage the frogs. I mounted it high so they could not jump past it. Its top is about 3 feet below the landing zone on the box. Do anyone think this would be adverse to the bats?? Maybe they do not like the odor of the wrap around grease ?? Think I will remove the grease and mount the old plate lower with the top of it painted black!

Bernie

[LarryH]

I installed some very slick flashing on mine yesterday, about 6' off the ground.  Since the bottom of the houses are 19' off the ground, this flashing should be low enough to not bother them but high enough to keep predators from getting past it.  The flashing reflects the sun pretty fiercely, but I'm hoping that won't bother the bats since they are 12' above it.  I thought of painting it, but was afraid that would reduce the slickness of it.

I cleaned off the grease after I put the flashing on the pole, but I was not too concerned about it.  I used some of the synthetic grease I had sitting in the garage, and it didn't have any noticeable smell -- but it sure was slick! 

I did an exit count last evening to see how many bats were still in the houses as hot as it has been, and I counted 132 of them, mostly little browns.  This was down quite a bit from the last count I did, but it was better than I expected.  Right after they went out for the night, we had a fierce thunderstorm and a cool front which probably caused them to return to the houses early.

 

 

 

[kerbat]

The population in the rocket continues to vary widely. It may just be the location, but they did come back strong after I removed the wrap around that was 3 feet under the entrance with wheel bearing grease on it. Painted the pie predator plate black and mounted it back at head height. The frogs have not been nearly as many but still have a few. The weather locally has changed to thunderstorms every afternoon and the roads have been full of dead frogs.

[Joe Spencer]

Check out the post by Kent below though not directly relatable: 

 http://www.batnic.org/forum/forum3/492.html

[kerbat]

Thanks Joe, I had read this thread earlier. My old bat house mounted on the house only eight feet hope was mowed under regularly and as far as I know had no effect on the bats. My rocket is considerably higher and it also gets mowed under regularly on one side.

It is hard to believe that gasoline engine exhaust bothers the bats since large colonies live under auto bridges with bumper to bumper traffic! I believe it is possible the grease gave off bad fumes when it got hot early morning when there was no breeze and would collect in the house.

Bernie

[Erik]

Hi Bernie,


across the Atlantic, I have the same experience with gasoline / oil fumes and its negative effect on bats. I am also often surprised of bat roosts in bridges with a lot of traffic underneath, but than those places are also very windy, so fumes never get very strong.
In our province in The Netherlands we have a few old underground bunkers that are used by bats as a winter roost. In two of those bunkers, the bats had to enter the bunker through a room that was used as a garage. Because of oil storage and parked vehicles (mostly for agricultural use) there was always a strong gasoline / oil fume. We talked to the owners and convinced them to stop using that room as a garage and move the garage to another building.
After that numbers of bats increased. Because of less fumes? We think so, but of course we have no clear evidence. But the rising fume levels under or in a bat house is logical reason for what you experienced with your bat house.


I also wonder if a predator guard can be too close to a bat house. When bats return to the roost in the morning they swarm a couple of minutes around the house. Free space around and underneath the bat house entrance can be a critical factor in bat house success. I would make sure there is at least 170 cm space between entrance and predator guard.

Greetings,

Erik 
(p.s. sorry for my strange English, it is not my native speech, but I do my best )