Bat House Forum

[Dave Miller]

Thanks Joe for getting your forum going again.   I remember when my hosting company went away and thus my forum, it was pretty disappointing.

As I mentioned in my post just before the forum went down, I have recently gotten involved with a nearby wildlife refuge (http://www.google.com/maps?hl=en&q=&ie=UTF8&z=14&ll=45.563403,-122.294912&spn=0.047953,0.068665&t=h&om=1).  I have floated the idea of building and putting up a few bat houses at the refuge and have gotten a cool response from the refuge manager and regional biologist.

I would like to hear from anyone who has experience working with wildlife refuges - best practices, etc.

Thanks,

Dave

 

[Joe Spencer]

Thanks for reposting it Dave.  It surely looks like an ideal area for some bat houses and occupancy. Indeed it is great to be back.   For those of you who don't know Dave,  Dave started bat house discussion in ernest a few years ago with Dave's Bat House Discussion Group.  It was extremely popular at the time and well received furthering interest in bat houses.   I'm grateful to Dave for starting such a wonderful resource.  Dave, it won't happen this year, but next year I am approaching the Oxbow wildlife refuge in my area which recently was expanded a few years after a military base closure.  I hope to get some bat houses up there...  

[Dave Miller]

Thanks Joe.  "A few years" - you're being kind!  I think it was close to 10 years ago - wow.

I think I archived the whole discussion - would you like to look through it?  I think it is all static html so it should be readable.  Let me know.

Regarding the refuge, I have a bit of an update.  I was recently invited to join the board of a "friends of the refuge" group that has been in the formation stage for a while.   Since refuge budgets are miniscule, many of the refuge projects get done by volunteers and donors.  e.g. this winter we are planting 2400 native shrubs and trees, all with volunteer labor, and about half the plants were donated (by the local Audubon society, businesses, and individuals).

Regarding bat houses - even though I got a cool reception initially, I am pretty optimistic - I just need to make my case carefully.  As I mentioned before, I think I will have to do some kind of basic bat survey first (those biologists are always into measuring things ).  Doing a survey that a bat biologist would be proud of is out of the question for me.  i.e. I don't have mist nets, rabies shots, heterodyne detectors, etc.  But, I do have one of the "Simple Bat Detectors" which is helpful in finding bats (not identifying them).  I am pretty sure there is no roosting space on the refuge currently (trees with exfoliating bark, hollow trees, cliffs/crevices, buildings).  So I'm sure any bat roost would be an improvement.  Any suggestions of how a non-professional can do some kind of survey would be greatly appreciated.  If nothing else I can just put up a house or two and do emergence counts.  But I suppose that only indicates the usage of bat houses, it wouldn't count how many bats were at the refuge before and after the houses were put up.

On a somewhat related note, one of the things that must be measured on the refuge is the usage of a trail along the southern edge of the refuge.  The refuge manager needs to get a count of how many people, dogs, horses, were the dogs on or off leash, etc. over a period of time.  I suggested that we look into using a "game camera" (e.g. http://www.reconoutdoors.com/) to snap a photo each time someone/something goes down the trail, day or night.  I have two questions for the group about this:

1.  Has anyone ever used a game camera?   What did you like and dislike about it?

2. Has anyone ever used a game camera to photograph bats?  Some models allow you to take a picture at some interval, say every 10 minutes, for weeks.  I'm thinking that the camera would be mounted under the bat house, looking up into the crevices.  I know guano on the lens could be an issue, but I'm not too worried about that.  I would think that an infrared camera with an infrared flash would work best.

I would hate to steer the Friends group or the FWS to spend several hundred dollars on something that doesn't do what we had hoped.

Thanks,

Dave

[Erik]

Hello Dave,

I have experienced the same cool reaction on the suggestion to put up bat houses in a nature reserve / wildlife refuge. Our bat workgroup has developed a project to use bat houses for a bat inventory survey. With this project we wanted to mount 400 small (one chambered) bat houses in 8 forest areas of our province. (I guess a province here is similar to a county in the US). 8 members of our workgroup are involved, each working with 50 bat houses.
So I wanted to mount my 50 bat houses in several clusters in a two nature reserves near my house and I contacted the natural landscape conservation foundation who owns the reserves. Their first reaction was fairly negative, they didn't want to put up artificial roosts for any species. Their aim was to manage the forest in a way that it provides natural roosts for all species. In Netherlands almost all nature conservation organizations have already banned all bird houses from there forest..... I agree with their view but:
1. only few patched of forest in that area are suitable for bats.
2. we know so little about forest-dwelling bats that we need more information on how and where they live to be able to protect them. In the Netherlands we normally use heterodyne or Time Expansion Bat detectors for bat surveys and those methods are very labour-intensive and can only be done at night of course. So we need a daylight method like bat house surveys to be able to see bats which are difficult to find / recognize by detectorwork and to make batwork accessible for more people.

So they agreed on putting up the bat houses in their forest as a research method. The bat house are mounted in clusters of 3-5 bat houses. Originally we agreed that when a cluster is not used at all after 3-5 years I have to take it away. But when a clusters is used within 3 years by more than one bat, we assume that bat species was already living in that area and than the bat houses can stay (= must stay as they are protected). During the 3 first years we involved them in the "Bat House Walks" we did to check te bat house and we made beautiful reports. Combined with some extra detector surveys we managed to gather so much information on the bat species in that area that the biologists from that foundation changed from "roost-negative" to very "bat-positive" The bat house can stay - also because almost all of the clusters are used. I check the house every 2-weeks and from April to October I count approx. 10-25 bats from different species each time I check. More about that later. 

Your case is a little different as it is likely that there are no bats roosting in that area and I guess you hope to attract a bat colony to the bat house. You can pursuade the  biologists by putting forward that:
- bats are effective in protecting the young trees and shrubs (and also nearby crop fields) from insect pests
- when - in the future the area has natural bat roosts, the bats are already familiar to that area.
Do you have / know occupied bat houses nearby? Invite the biologists to come and take a look and count the emerging bats. Big chance that they want that in their wildlife refuge as well!
Good luck !
Erik

[Dave Miller]

Hi Erik,

Your reply was exactly what I was looking for.  Thank you so much! 

I have inserted replies below.

Dave

[b]

Hello Dave,

I have experienced the same cool reaction on the suggestion to put up bat houses in a nature reserve / wildlife refuge. Our bat workgroup has developed a project to use bat houses for a bat inventory survey. With this project we wanted to mount 400 small (one chambered) bat houses in 8 forest areas of our province. (I guess a province here is similar to a county in the US). 8 members of our workgroup are involved, each working with 50 bat houses.
So I wanted to mount my 50 bat houses in several clusters in a two nature reserves near my house and I contacted the natural landscape conservation foundation who owns the reserves. Their first reaction was fairly negative, they didn't want to put up artificial roosts for any species. Their aim was to manage the forest in a way that it provides natural roosts for all species. In Netherlands

[indent]

Yes, I think that is what I am running into as well.  However they did allow one volunteer to put up "bird bottles" for purple martins, which have been very successful (though ugly, in my opinion).  These birds are extremely rare in our area, though they used to be plentiful.  Thus "desperate times call for desperate measures", I guess.

[/indent]

almost all nature conservation organizations have already banned all bird houses from their forest.....

[indent]

I agree as well.  However it takes a very long time to create a large, dead tree which is what most cavity-nesting creatures would use naturally, including some types of bats.  Thus in my opinion, we should be providing artificial cavities until there is a reasonable supply of "snags", and the reserve is managed as it would have been before people got involved (periodic fires, etc.).  By the way, on this refuge they do plan to use fire to maintain some of the habitat in its natural state.

[/indent]

I agree with their view but:
1. only few patched of forest in that area are suitable for bats.
2. we know so little about forest-dwelling bats that we need more information on how and where they live to be able to protect them. In the Netherlands we normally use heterodyne or Time Expansion Bat detectors for bat surveys and those methods are very labour-intensive and can only be done at night of course. So we need a daylight method like bat house surveys to be able to see bats which are difficult to find / recognize by detectorwork and to make batwork accessible for more people.

So they agreed on putting up the bat houses in their forest as a research method. The bat house are mounted in clusters of 3-5 bat houses. Originally we agreed that when a cluster is not used at all after 3-5 years I have to take it away. But when a clusters is used within 3 years by more than one bat, we assume that bat species was already living in that area and than the bat houses can stay (= must stay as they are protected). During the 3 first years we involved them in the "Bat House Walks" we did to check te bat house and we made beautiful reports. Combined with some extra detector surveys we managed to gather so much information on the bat species in that area that the biologists from that foundation changed from "roost-negative" to very "bat-positive" The bat house can stay - also because almost all of the clusters are used. I check the house every 2-weeks and from April to October I count approx. 10-25 bats from different species each time I check. More about that later. 

Your case is a little different as it is likely that there are no bats roosting in that area and I guess you hope to attract a bat colony to the bat house. You can pursuade the  biologists by putting forward that:
- bats are effective in protecting the young trees and shrubs (and also nearby crop fields) from insect pests
- when - in the future the area has natural bat roosts, the bats are already familiar to that area.
Do you have / know occupied bat houses nearby? Invite the biologists to come and take a look and count the emerging bats. Big chance that they want that in their wildlife refuge as well!
Good luck !
Erik

I like the young trees and shrubs angle - we are in the midst of planting 2000 trees and shrubs in one area of the refuge.  We go to considerable lengths to protect them from beavers, voles, etc. but not insects.  There is also the mosquito angle, though I believe bats only eat mosquitoes opportunistically (i.e. when there are no moths or beetles available).  But still that is better than nothing.

I would guess that there are bats feeding at the refuge, that roost somewhere in the forest north of the refuge, or perhaps south across the river.  I would be really surprised if there are any occupied bat houses in the area (and mine is 7 miles away, only occupied occasionally).  I do have a friend that lives about the same distance from the river as the refuge, that has had a bat colony in their attic for at least 30 years.   I could take the refuge manager and biologist there.

I am very interested in your surveys and reports - would you be willing to share some of them with me?  I don't mind if they are in dutch - I am mostly lookng for the layout and general content.  I have never done a wildlife survey and don't have appropriate forms, techniques, etc.  I am especially interested in your "beautiful reports".

Thanks,

Dave

[Dave Miller]

Good news - the refuge manager has given me the green light to place a bat house on the refuge.  I am not allowed to put up a pole thus I will be placing it on one of several standing dead trees whose branches are mostly gone.    Fortunately they have relaxed the requirement to do a bat survey first.  I convinced the refuge manager that it would be easiest to just count the bats in the house (or as they emerge).  There is a big habitat restoration project in that area with volunteers coming out to water nearly every evening throughout the summer.  I plan to train them on counting bats in the house and ask that people record counts each time they water.  This will both raise visibility about bats to many people and provide the biologist with some data.

I am working up a design that uses 12" square slates as the exterior, for the following reasons:

• Looks - the refuge managers are very sensitive about placing anything artificial on the refuge.   Generally speaking, they do not even allow cedar bird houses.  The slate will blend nicely with the dead tree that it will be attached to.
• No painting required - the slate is already the right color for our area (dark gray).  No painting also means no re-painting, i.e. less maintenance.
• Longevity - I expect that slate will last longer than even cedar.  Probably longer than the dead tree.  I will keep an eye on the tree and when I think it is ready to fall, I'll move the house to another tree. 
• Thermal mass. 
• Cost - I got the slates at Home Depot for about $2 each. 

Of course the down sides are increased weight and more difficult construction.   But this should be a fun project.  I also hope to incorporate some learnings from Kent re: the "Oregon Wedge" design.  The interior and back will be cedar, with grooves cut into the smooth surfaces.  I realize this is a lot of labor but I only build one bat house every 15 years so I don't mind .

[Joe Spencer]

Good news indeed Dave! Looking forward to the pics during/after construction if possible.  After casing the site, how does the sun exposure look at this point on the selected tree? Looking forward to your updates.

[Terry Lobdell]

Dave, that is great news! I like the idea of the slate.......here in nw pa we have lots of bats under slate roofs. How big are the slates?

[Dave Miller]

To answer some questions:

Sun exposure?

The dead trees in question get full sun pretty much all day.  BTW, the trees were killed by beavers, quite some time ago.  One of the trees (which I will not be using) has a hollow branch that is used by purple martins for nesting.  Purple martins are quite rare in this area and there is a project at the refuge to restore their population here.  This hollow branch is one of only three natural purple martin nesting sites in the whole state.

You can see some of the dead trees in this picture: http://inlinethumb19.webshots.com/13522/2611588070074310452S600x600Q85.jpg

There is one at the far left in this picture: http://inlinethumb53.webshots.com/4340/2135923670074310452S600x600Q85.jpg

In the last picture you can get an idea of the environment.  The trees are cottonwoods, some quite old.  This particular spot was once a seasonal island (during the spring floods).  In the 1960's a dike was built along the Columbia to enable development of the land for industrial purposes (at one time a nuclear power plant was planned to be built here).  The one problem with that idea was a creek which drained into the land behind the dike.  So they re-routed the creek to create a sort of raised aqueduct which ran down the middle of the former island.  Thus the trees now have a creek running through them.  For those of you familiar with this area, that is Crown Point in the distance.

 

How big are the slates?

These are 12" square slate tiles.  I am tentatively planning to use about half a tile for the roof, and 2-1/2 tiles for the front.  I think the sides, back, and partitions will be cedar.  

I will try to remember to take some pictures during construction.

 

I was out at the refuge watering a week ago and we saw about 5-10 bats on the way out just after sunset.  I think they were a mix of big brown & little brown, but that is just a guess.  I tried to get some pictures, this is the closest I got: http://inlinethumb28.webshots.com/13531/2879447820074310452S600x600Q85.jpg.  I edited this a bit to make the bat easier to see: http://inlinethumb16.webshots.com/13455/2803970500074310452S600x600Q85.jpg

You can just make out a bat to the left of center of the photo.  As you can see there were many insects in the area, and thus many bats.  We also saw several owls.

[Joe Spencer]

Dave error with photos posted above:

Forbidden You don't have permission to access /464/5/88/7/2611588070074310452zZWGAY_fs.jpg on this server.

[Dave Miller]

Dave error with photos posted above:

Forbidden You don't have permission to access /464/5/88/7/2611588070074310452zZWGAY_fs.jpg on this server.

Sorry about that, I didn't realize that I was posting the "logged in" link.  I have edited my posting with updated links that should work.  Let me know if you want to see these in their original size (which are much bigger).