Thursday, 9 July 2015

How to Make a Simple Bat House

I've been making and selling 'BAT CHECK' bat houses for quite a while now (available at Living Rooms and Birds 'n Paws in Kingston, ON)  Here's a relatively easy model to build. You'll need some basic tools (handsaw, hammer, drill).  A table saw or 'chop' saw will make it even easier.  Count your fingers before and after to see that the numbers match!

To make one bat house you'll need:

1)  a piece rough lumber (3'  x 6 - 8 " wide x  3/4" to 1" thick).   (A rough surface gives the bats a good grip...smooth wood should be roughed up!)

2)  16 nails (2" galvanized,spiral)

A)  THE CUTS:   These are the lengths I use.  The board pictured is 6" wide.

BACK (15").  Note that I put 10 shallow, cross-cuts to form a 'ladder' for easy access. These are not necessary with a rough board.  Two 1/4" holes, one at top center and one at bottom center, can be drilled through the back piece before assembly.

SIDES (12").  Cut a sngle 12" piece & then  make a mark 5" from the end of one edge. Rotate the board and mark the opposite edge (same side!) at 5" too.  Connect the marks and cut the piece to yield two side pieces, each with a sloping top (fig. 1).

ROOF (9"+).  9" works if the board is 3/4" thick.  Go to 10" if the board is 1" thick.

FRONT (5").  My houses have a bat logo and a tag.  Blank is fine :)

BOTTOM (3.5").  This piece varies somewhat in length depending on the thickness of the board.  3.5" should do for most houses.


I enclose the following illustrations with my Bat House Kits.  I'll add a few more details for you.

Fig. 2.  1st SIDE.  Align the 'pointed' end of one of the sides about 2" down from the top of the BACK piece.  Attach using two nails as shown.

Fig. 3. FRONT.  Tip the BACK onto its edge and align the FRONT as shown.  Make sure it's flush along the top edge (or the roof won't fit well) and along the front edge.  Nail as shown.

Fig. 4. 2nd SIDE.  Align with and attach (2 nails) the second SIDE to the FRONT piece first to avoid alignment problems. Next, align it along the BACK and add two more nails.

Fig. 5. INSERTING the BOTTOM.  Tip the bat house upside-down and rest it on the edge of a bench / table.  Slide the BOTTOM piece into the opening immediately behind the FRONT piece.  

Fig. 6. CREATING the ENTRANCE.  Angle the BOTTOM piece towards the BACK piece to create a narrow doorway.  The bottom edge of the BOTTOM piece should be flush with the SIDE pieces and the opening should be about the width of your index finger (approx. 3/4").  Too big and other critters get in.  Too small and you might be lucky enough to get bees.

Fig. 7. ATTACHING the BOTTOM.  Place the bat house on its side and sight up the sloping BOTTOM to align the nails.  Use your fingers to wedge & hold it in place (this is the most finicky piece).  I usually put in a nail at the bottom of one side, then flip it over and repeat on the other side.  Thus you can pivot the top edge of the BOTTOM piece tight against the back of the FRONT piece and put in the remaining two nails.  Got it?  Got it!  :)

Fig. 8. ROOF.  Center the roof on the top of the SIDES.  Two nails in each SIDE completes the job!

There's a tweak you can incorporate if you have a table saw or plane of some sort.  If you look closely at Fig. 8 you'll notice that the top edge of the ROOF is beveled so that it fits snugly against the BACK. 
Find this angle using one of the SIDE pieces.  It's not crucial but it shows better craftsmanship (not to judge!)

DONE!  The bat house in the picture below is decked out with instructions and an envelope of bat droppings.  Some people think that the bat droppings are essential for success - giving the house a 'lived-in' (i.e. 'safe') aroma.  Bats actually show no preference for bat houses with or without the guano, so just put it up!

There is no ONE best location for your bat house because different species have different needs, as do bats of different sexes and of different stages in their life.  Some bats are exclusively tree-dweller, and are unlikely to use a bat house.  Pregnant females often seek out very warm (e.g. attic) housing during gestation and early rearing of the young, but once the young are volant (capable of flying) the females and the young-of-the-year (y.o.y.) look for cool places so that they can drop their metabolism to conserve energy and fatten up for hibernation.  Males often roost separately from the females (and y.o.y.) and stay in cooler day roosts.

I recommend attaching the bat house to a structure with a south or southwest exposure.  10' or so up keeps it out of reach of most pests (cats, squirrels). Buildings tend to be more secure and less exposed to the weather.  Try up under the overhang of your roof.  If you use a tree, make sure that there is sufficient space around the bat house for easy launch and return.  3 ' or so below the entrance will allow them to get flight speed when they head out at night.  When they return bats often 'touch-&-go' several times before committing to the return.  Seems to be a defensive behaviour just in case there's a predator awaiting their return.  

Anyway...I hope this is if use!

My next project is a BIG bat house - a bat condo, if you will - that will hopefully be suitable for a maternity colony.  More on this later.


1 comment:

  1. I love making things by hand! Specially if they are gifts for someone special to me! I will be making this for my husband! :)