Here is an easy method to discourage house sparrows from invading and “taking over” your bluebird nest box ……………………… ADD A SKYLIGHT !!
House sparrows are and have been the bluebirds’ #1 Enemy; so let’s get started on “how to” prevent them from driving your bluebirds away.
If you have an old nest box or a new one, this technique will work.
You will need:
1) 1/4″ power drill
2) 2 1/2″ hole saw
3) 4″ x 4″ plexiglass piece (1/4″ works great)
or 8″ x 11″ twin-walled polycarbonate (Lexan)
4) 4 copper screw nails/brads for plexiglass
5) tube of silicone caulk for plexiglass
6) 1/16″ drill bit for brads; 1/8″ drill for screws
7) tape measure & straight edge
8) hammer for plexiglass
4 – 3/4″ screws and screwdriver for Lexan
First, locate the center point on the roof of your box and puncture
the spot with a nail; then drill a 2 1/2″ hole completely through the top. Second, position your plexiglass or over the opening and hammer a copper brad into each corner, 1/4″ in. (pre-drill the holes in the plexiglass with 1/16″ bit). Third, place a bead of silicone caulk to seal the plexiglass on all 4 sides.
If you are using the twin-walled polycarbonate (Lexan) as demonstrated in the YouTube video, pre-drill 4 holes in each corner
1 1/2″ from top & bottom of roof and fasten with 4 3/4″ screws.
Congratulations !! You are finished and can install your bluebird box to its desired location. I have used this “Bluebird Box Skylight” technique on many “sparrow-infested trails” with great success. Nothing is 100% effective (“Sparrow-proof”) when trying to discourage house sparrows but I think you will be happy with your results. It is worth a try ———————- just 15 minutes of your time and a couple dollars in cost.
GOOD LUCK !!