Bat Houses in Alaska
Watercourses,
ponds, lakes, and open meadows adjacent to woodlands are attractive areas for
bats. The open areas and water features
mean that insects will be abundant and flyways will be relatively clear of
obstructions; the mixed forest provides cover and roosting opportunities. If your home is already near a water feature
or open space, your chances of attracting bats will be improved. Temperature
is critically important for roosting bats - especially here in the far
North. I'd recommend choosing a location with a generally southern
exposure; The warmest locations will be
those facing Southeast, South, Southwest, or depending on the location of your
property, even West and Northwest. You
may choose to put up a couple of bat houses facing different directions: One facing South, and another facing
South-west or West for example. Providing a couple of houses with a range
of temperature conditions can either be an experiment for you to figure out
which location(s) the bats prefer, or it will give resident bats a range of
available temperature options for changing weather conditions.
How?
I recommend a simple, single celled, smallish, design (as
bat houses go). You can either build your own (using plans from one of
the links below) or buy pre-made bathouses from organizations like Bat
Conservation International. A bat house
is generally between one and two feet across, about two feet long, and only
about ¾ to one inch “deep.” They can be
made out of plywood (NOT pressure treated plywood – it can be toxic to bats) or
as an alternative to plywood, you can use large, untreated wood shingles (shake
siding shingles) to construct the house.
The shingle versions may look a little nicer (kind of rustic?) if
attached to your house, but the edges won't be as tight and you'll want to be
sure to calk the edges to keep water and drafts out (not a bad idea regardless). The rear vertical surface inside the bat house is either covered with a plastic
mesh (never metal) or has fine grooves to provide traction for the bats. The use of rough shingles might obviate the
need for cutting in traction grooves or installing plastic mesh.
Many
of the nice looking bat houses pictured on the pages below are naturally
finished wood - However, here in Alaska I suggest a dark brown or black
stain or paint to increase the amount of heat absorbed from the sun. Use
only water-based stains/paints, not oil-based. Mount the bat house high
on the side of a building with a clear flyway in front - avoid obstructions and
branches and bright night-time lights. If you don't want to attach it to
your house, you can use the trunks of deciduous trees (meeting all the other
qualifications). Many bat house
experts recommend using a metal pole for mounting your bat house house instead
of a tree. Their logic is that the pole
makes it easier for bats to find the house and that it provides protection from
possible predators. However, I think
trees can be good options here in Alaska. Common wisdom is to put them up
high - greater than 12 feet - but I've had bats roost in the siding shingles of
our old cabin just a few feet above the deck. It was a warm, warm
spot.
The
last piece of advice is to be patient - if your house hasn't attracted
occupants after two years, experiment with putting it in different locations.
Simple,
single-cell bat house designs:
http://www.batcon.org/bhra/economyhouse.html
http://www.town.gladstone.mb.ca/1ChamberBatHouse.pdf
http://www.batconservation.org/content/buildyourown.htm
Pictures of nice
looking, simple houses:
http://batroost.com/index.asp?PageAction=VIEWCATS&Category=200
Mesh for lining
a bat house (don’t use metal meshes):
http://batroost.com/index.asp?PageAction=VIEWPROD&ProdID=25
If
you haven’t seen it already, check out our website www.akbats.net, and I'd appreciate knowing the outcome of
your efforts as well as any bat sightings you may have through the summer.
David
Tessler