You will need:
• Rough cut, unplaned, untreated, softwood timber, 15 cm wide x 150 cm long x 1.5 cm thick
• Scrap rubber, such as an old inner tube from a tyre
• Galvanised 20 mm (3/4") nails
• Pencil and ruler
Designing your nestbox:
There is no standard, accurate design for a nestbox. Birds do not insist on their nest sites being mathematically precise! What they do require is a nest site which is secure and weatherproof, and as safe as possible from predators. So, make the box to suit the materials available, rather than buying materials to match any given dimensions.
Making your nestbox:
- Mark out the panels of the future nestbox with pencil and a ruler, and write the name of each panel onto the marked out wood.
- Saw the panels apart. You will need to make a slanted cut between the front panel and roof at a 45-degree angle.
- Decide which box type you want to make and adjust the front panel accordingly:
- Hole-fronted tit box – use a hand brace or drill to make a round entrance hole: 25 mm diameter for blue tits;28 mm diameter for great tits; 38 mm diameter for sparrows
- Open fronted robin box – simply saw off 75 mm from the top of the front panel to make a ’window’ entrance.
- Start constructing your box by nailing one of the sides onto the back plate through the back.
- Nail on the floor (this can be quite tricky – go carefully to avoid splitting the wood).
- 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.
- Fix on the roof panel with a rubber flap ’hinge’ made from scrap rubber. This should cover the join between the roof and back plate completely, so it is 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 be able to lift away like a lid.
- After construction, treat the outside of the box only with a water-based wood preservative product, such as 'Cuprinol' or 'Sadolin' (not creosote), to prolong its life and help repel water. If using planed timber, clear polyurethane may be used instead.
- If you have it, fix a piece of roofing felt to the roof to prolong the life of the box and render it even more waterproof.