|
Little
Brown Bat - Illustration by Michel Poirer
for
bats
putting
up a bat house
The scarcity of suitable roosting sites threatens bats'
survival. Putting up bat houses is a great way to help bat
populations. To increase the chance of enticing bats to
take up residence in your bat house(s), consider the following:
-
Temperature is a critical factor in roost selection. In
Canada, bat houses should receive at least ten hours of
direct sun each day, and more is better.
- Mount
bat houses on poles or on the side of a building at least
12 feet (4 metres) above the ground (the higher the better).
Houses mounted on trees are more difficult for bats to
find and more vulnerable to predators.
- Bats
need to drink water every night, so houses located less
than a quarter mile (400 metres) from a water source,
such as a stream, river, or lake, have the greatest success
in attracting bats.
-
Bats like a clear swoop zone to get in and out of their
roosts, so avoid placing the house in an area where there
are a lot of obstacles, such as tree branches.
-
Placing two or more houses in one location allows bats
to better respond to changes in temperature by allowing
them to move between the houses as needed.
-
Do not mount houses close to bright lights.
- In
Canada's cold climate, bat houses should be painted black
or dark brown to increase the inside temperature. Use
water-based paint or stain, not oil-based. Apply three
coats.
- Be
sure to use untreated wood for your bat house. Pressure
treated wood may contain chemicals harmful to bats.
- The
inside of bat houses must be roughened to allow bats to
grip. Create horizontal (not vertical) scratches or grooves.
Space cuts roughly ½ inch (13 mm) apart and 1/16
or 1/32 inch (1 or 1.5 mm) deep. An alternative is to
attach plastic (not metal) screening flat on the wood
surface to avoid injury to the bats.
- Be
sure to caulk all seams, especially around the roof, to
prevent drafts and keep temperatures stable.
- Use
exterior grade or galvanized screws rather than nails.
- If
after two years your bat house has failed to attract occupants,
try moving it to a new location.
two-chamber
rocket box | hot under the collar
two-chamber
rocket box
 Materials
List
- One
2-inch (5-cm) inside diameter metal pole (2½ inch
(6.4 cm) outside diameter), 20 feet (6 metres) long
- Two
1 x 10-inch x 8 feet rough-cut cedar or pine (¾
inch x 9¼ inch x 8 feet finished). Cut each board
into two lengths of 36 inches (90 cm). Keep one leftover
piece to make the roof cap.
- Two
1 x 8-inch x 8 feet rough-cut cedar or pine (¾
inch x 7½ inch x 8 feet finished) cut to ¾
inch x 6¼ inches x 8 feet. (Keep leftover strips
to make spacer blocks.) Cut each board into two lengths
of 42 inches (105 cm).
- Two
1 x 4-inch x 8 feet rough-cut cedar or pine (¾
inch x 3½ inch x 8 feet finished) cut to ¾
x 3¼ inches x 8 feet. Cut each board into two lengths
of 45 inches (112 cm).
- One
box of 100 deck screws (Robertson) - size 8 x 1¼-inch
- One
box of 100 deck screws (Robertson) - size 6 x 1-5/8-inch
-
One tube exterior latex caulking (paintable)
- Two
quarts (2.26 litres) flat latex exterior paint - black
or dark brown
- One
sheet-metal roof (as illustrated) or one square plastic
roof vent (more economical and easier to find)
- One
fence bracket to fit the pole
- Four
2-inch (5-cm) screws
Instructions
- Rocket
boxes were originally designed to fit over a 4 x 4-inch
(10 x 10-cm) wooden post (untreated). To increase durability,
the following directions replace the post with a wooden
pole sleeve attached to a metal pole.
- You
can try mounting the rocket box on a building, but place
it on the south or southeast side to get the most sun.
Close off the bottom of the pole sleeve with leftover
board to keep wasps or hornets from taking up residence.
- The
two-chamber rocket box consists of 3 shells (as illustrated).
(The extended length of the inner shell and pole sleeve
acts as a landing surface for the bats.) Each shell is
a perfect square.
- The
heights given for the box shells should serve as a minimum.
The box can be made taller.
- ¾-inch
(20-mm) finished size of lumber is required because ¾
inch (20 mm) spacing is critical for the roosting chambers.
If another size lumber is used, the dimensions must be
adjusted accordingly.
Pole
Sleeve
-
Assemble the four 45-inch (112-cm) boards into a box using
1-5/8-inch (4-cm) screws and caulk.
- Roughen
the outer surface on each side (see "Putting
Up a Bat House").
- Cut
40 spacer blocks from the ¾-inch (20-mm) strips
of finished lumber scraps, approximately 3 inches (7.5
cm) long. (Helpful hint: when marking off for cutting,
indicate the side to be attached to the box to give ¾-inch
spacing for the chamber.)
- Cut
8 spacer blocks from the ¾-inch (20 mm) strips,
approximately 6 inches (15 cm) long.
- Drill
one 1/8-inch (3 mm) hole at both ends of each spacer block
to prevent splitting. Smooth any rough edges on the spacers.
- On
three sides of the pole sleeve, attach two spacer blocks
(one on the left, one on the right) at the top and center,
using 1¼-inch (3.1-cm) coated deck screws (two
screws per spacer). Attach the two bottom spacers 8 inches
(20 cm) from the bottom of each of the three sides.
- Repeat
this procedure on the fourth side using four of the 6-inch
(15 cm) spacer blocks at the top and 8 inches (20 cm)
from the bottom.
Inner
Shell
- Roughen
both sides of each of the four 42-inch (105-cm) boards.
- In
two of the boards, cut a 1½-inch (3.75-cm) circular
hole using a 1½-inch (3.75-cm) hole saw (for bat
passage between chambers), centered horizontally, about
10½ inches (26 cm) from the bottom end. Sand the
hole to remove any splinters. The passage holes will be
on opposite sides of the house.
- Assemble
three of the boards into an open box using 1-5/8-inch
(4 cm) deck screws and caulk.
- Place
the pole sleeve into the inner shell (bat passage holes
to the bottom) so that the side of the pole sleeve with
the longer spacer blocks is to the open side. Align the
top of the pole sleeve with the top of the inner shell.
- On
the fourth 42-inch (105-cm) board, mark the position of
the top and bottom spacers.
- Attach
the fourth board to the inner shell using 1-5/8-inch (4-cm)
deck screws and caulk.
- Secure
the inner shell to the pole sleeve by screwing two 1-5/8-inch
(4 cm) deck screws into the centre part of each of the
6-inch (15-cm) spacer blocks. Ensure the screws do not
protrude into the roosting chambers.
- Attach
spacer blocks to the outside of the inner shell following
the same directions as for the pole sleeve.
Outer
Shell
- Roughen
the inside surfaces of the 36-inch (90-cm) boards.
- Assemble
the outer shell and attach to the inner shell following
the above instructions. (Note: do not drill bat passage
holes into the outer shell.)
Roof
- For
the roof cap, measure the outer shell and cut accordingly
using the leftover wood from your 9¼-inch (23.5-cm)
wide board. (Note: This will not cover exactly, so you
must centre the piece, then caulk and screw.) Caulk all
edges and attach to the box with 1¼-inch (3.1-cm)
deck screws. Carefully drive the screws in the top edges
of the outer shell to prevent them from straying into
roosting chambers.
- Attach
a sheet metal roof (as illustrated),
pop riveted, caulked, and painted black.
OR
- Unclip
the roof vent top from the bottom piece. Apply caulking
generously to the underside of the vent top and set firmly
onto the roof cap. Do not screw on.
Final
Steps
-
Paint the outer surface of the box (see "Putting
Up a Bat House").
- Attach
the fence bracket to the bottom of the pole sleeve using
four 2-inch (5-cm) screws.
- Place
the pole into the fence bracket and tighten with the bracket
screw.
- See
"Putting Up a Bat House" for
ideal placement.
These
plans were adapted from a design by John Wilcox generously
provided by Bat Conservation International (BCI). Please
report successes or failures with your bat house to BCI
at (512) 327-9721 or mkiser@batcon.org.
CWF
would like to thank Bat Conservation International for their
help. For more information on bats or bat houses check out
their very informative website at www.batcon.org.
Illustrations
by Michel Poirier
bats
meet birds
imagine
...bats and birds living together. Often coexisting in snags
and artificial structures, these odd housemates get along
remarkably well. Most bats and birds work separate shifts
- nocturnal and diurnal - and are not at risk of infecting
each other since they carry different parasites. The best
way to preserve this happy marriage is to save snags. (These
standing dead trees are also homes to countless other creatures.)
The next best resort is to provide artificial accommodations.
Rather
than building separate structures, why not meet the needs
of both bats and birds in a single structure with different
compartments? The following
design will lodge big brown, little brown, pipistrelle,
and other colonial bats, plus migratory birds as tree swallows
and great-crested flycatchers. With modifications, it will
house other cavity-nesting birds, from wood ducks to woodpeckers.
- Use
2 cm (3/4") softwood lumber, such as cedar or pine. Do
not use pressure-treated wood. It can be toxic to young
bats and birds.
- Cut
the front, sides, floor, roof, back and partitions.
- Bore
an entrance hole in the front panel (4 cm in diameter
for bluebirds and tree swallows, 5 cm for great-crested
flycatchers) 4 cm from the top.
- Drill
small drainage holes on the side panels, just above the
floor.
- Saw
shallow, horizontal grooves (2 mm deep and 1 cm apart)
on the inner surfaces of the bat section, including the
walls and roost partitions, to enable bats to crawl inside.
- Assemble
the pieces according to the construction plan, using 4
cm (2") coated flat-head screws and bond-fast glue. The
opening between the roost partitions should be 2 to 2.5
cm wide.
- Paint
the outside of the structure dark brown or grey.
- In
early April, choose a site near a lake, pond, marsh, stream,
or river with plenty of insects, ideally inhabited by
the species you hope to attract.
- Hang
the box 3 to 5 m off the ground on a tree-trunk or, preferably,
the side of a building that faces east or southeast and
catches the morning sun. The spot should be sheltered
from the wind and at least 6 m from neighbouring trees.
To prevent house sparrows and European starlings from
moving in, leave the entrance to the upper compartment
covered until bird migrants appear in spring.
- Have
patience. Your structure may remain vacant for a year
or two, but its dual purpose doubles the chance that bats
and birds will eventually move in.
- Clean
the box each fall and ensure that it stays in good repair
hot
under the collar
Much to the surprise of wildlife biologists, sheet-metal
collars wrapped around trees not only protect nesting
birds from predators but also create ideal roosts for bats.
Corrugated metal, loosely fitted, allows bats that normally
roost under bark to regulate their temperatures by crawling
around a tree to the sunny or shady side. Unlike loose bark,
these metal collars can by placed where needed and last
for years. They should be at least a metre wide, secured
along the seam with aluminum nails, and have enough space
underneath (two or three centimetres wide) that bats can
enter and move around
top
 QuickPrint
|
