Making A Bird Box

How to make a bird box
Making and installing nestboxes for garden birds
There's no hole like home...

Many garden birds nest or roost in hollow trees and holes in trees. Unfortunately, these days most old and dying trees and branches, which offer the best nesting and roosting sites, are routinely cut down and removed. This leaves fewer places for birds to set up homes and raise families.
Specially constructed nestboxes imitate the holes and cavities in dead standing wood that are usually cleared away. A birdbox can be a real help to garden bird, an estimated 2 million fledglings are reared in nestboxes each year. And it's a wonderful feeling to see a blue tit or robin investigating a nestbox that you have made and put up yourself.
What's more, building birdboxes is straightforward and easy, no special carpentry skills are needed.
There are many different designs and materials that may be used, but for simplicity and ease of construction, a basic plan is given below.

Box building instructions:
You will need:
Roughcut, unplaned, untreated softwood timber, 150 mm wide x 1500 mm long x 15 mm thick
Scrap rubber, such as an old inner tube FROM a tyre
Galvanised 20 mm (¾") nails
and carpentry saw, hammer , hand brace or drill (with 25 mm, 28 mm, or 32 mm diameter cutting bits), pencil and ruler, scissors for cutting rubber the following tools:

1. Marking out
Mark out the panels of the future nestbox with pencil and ruler to the dimensions shown above, and write the name of each panel onto the marked out wood (believe me, this will save confusion later). Where possible, try to ensure that the grain will run vertically in the finished box; this will help drainage.
2. Cutting

Saw the panels apart. Please note that you will need to make a slanted cut between the front panel and roof, at a 45 angle
Front panel: decision time! Decide which box type you want to make:

Hole fronted tit box - use a hand brace or drill to make a round entrance hole of:
25 mm diameter for blue tits
28 mm diameter for great tits
38 mm diameter for sparrows
Note: The entrance hole should be no less than 125 mm FROM the floor level
Open fronted robin box - simply saw off 75 mm FROM the top of the front panel to make a 'window' entrance

3. Nailing

Start by nailing one of the sides onto the back plate through the back (as in the diagram); then nail on the floor (this can be quite tricky go carefully to avoid splitting the wood); then nail on the other side panel
Nail all the other panels INTO place except for the roof panel
If your carpentry is of a high standard with evenly proportioned panels and snugly fitting joins, you will need to drill some small holes (1-2 mm diameter) INTO the floor panel to allow for drainage

And finally...

Fix on the roof panel with a rubber flap hinge made FROM scrap rubber. This should cover the join between roof and back plate completely so as to be waterproof. Nail the rubber INTO the back plate first, then pull it tightly over the join and nail it onto the roof. The roof should open and close like a lid.

Wood treatments and preservatives
These will prolong the life of your box, but are hazardous to wildlife, and fatal to bats, which may use the box. If you must treat your nestbox, products such as Fenceguard, Cuprinol, Sadolin PX65 may be used, but should not be applied around the entrance hole nor inside the box. Even without treatments a nestbox should last 5-10 years.