Bird Box Mk I

This simple design is based on those provided by the RSPB and many other wildlife agencies. It can be simply constructed from a plank of wood measuring 1500 mm x 150 mm and between 15 mm and 24 mm thick.

It is very important that your timber does not contain any harmful chemicals. Untreated ‘carcassing’ from your local timber merchant is ideal.

You’ll need a few simple tools and materials to complete this project and it is best to have these to hand before you start. A hammer is essential as are nails for fixing (50 mm bright round wire nails are most suitable). To fix the roof you will need a strip of rubber or similar to make the hinge (old bicycle inner tubes and offcuts from pond liners handy here!) and some 20 mm netting/fencing staples to make the ‘eyelets’ to tie the roof in place. As with many Go Wild projects the design can be altered slightly to suit the fixings and materials you have available.

Stage 1: marking out and cutting your plank

Bird Box Mk 1 - marking out planMark out your plank as shown in the diagram. (Go Wild Tip: You will need to make some allowance for the width of your saw blade)

* The dimension of the base will depend on the thickness of your wood. The illustration shows the dimensions for a plank with a thickness of 22 mm.

The formula for calculating the base dimension is:

width – ( 2 x thickness )

For our plank this gives us:

150 mm – 44 mm = 106 mm

As shown here it is advisable to reduce this figure by a millimetre or two to afford easier assembly.

All the cuts with the exception of that between the front and roof pieces should be made perpendicular to the plank face.

As shown in the diagram to the left the cut between the front and roof pieces should be made at an angle that matches the slope of the sides. This ensure that the front and roof pieces fit correctly during assembly.

(Go Wild Tip: Cut the sides first and use them to mark the correct angle before cutting the front)

With all the sides cut it’s time to drill the entrance hole in one of the side pieces (I use the sides in preference to the front as it provides more space for the birds to fill up with nesting material and keeps the chicks further away from predators). The minimum size for the hole should be 25 mm for Blue Tits, 28 mm for Great Tits and 32 mm for House Sparrows. Generally speaking I’ve found no problem with Blue Tits using boxes with 28 mm entrance holes often in close proximity to a box housing Great Tits.

Stage 2: putting it all together

Before reaching for the hammer take some time at this stage to ‘dry fit’ all your pieces. This will give you a better idea of where the pieces go before you nail them together and will allow you to make any necessary adjustments. Don’t worry if there are small gaps between the pieces as this will aid ventilation and prevent the box from overheating during use.

Next place all your pieces, hammer and nails on a level, hard surface (concrete drive, paving flags) and you’re ready to begin.

(Go Wild Tip: Blunt your nails by placing them point up on a hard surface and tapping the point lightly with the hammer. Why? Using blunt nails reduces the risk of the wood splitting when nailing together)

First take the base and one of the sides and place them together as shown in the diagram. (Go Wild Tip: Knock the two nails almost all the way through the side piece before positioning the two pieces – that way the first tap of the hammer will secure them in place)

This first stage is the most tricky as the pieces tend to wobble about – if you can call on anyone to assist you this is the time you need them most!

Turn the assembly you have just made so that it rests on what will be the front of the bird box.

Place the back piece on top of the side/base assembly leaving an overhang of about 85 mm at the bottom.

Ensuring that the side is properly aligned with the back and the base is at right angles secure the back using four nails as shown.

Turn the box so that the missing side is facing you – it should still be resting on the front. Position the remaining side and fix using three nails driven through the back piece.

The assembly should become somewhat easier from now as the box becomes more solid.

Turn the box again so that the first side is resting on the ground and complete the fixing of the second side using two nails driven into the base as shown.

You’re now past the half way marker!

Place the box with the back piece resting on the ground and place the front on the top, taking care to get the angled end lined up with the sides.

Fix the front permanently in position using four nails and place the box to one side while you fix the rubber hinge to the roof.

Place the roof on the ground with the longest side facing uppermost. Cut a piece of rubber 150 mm x 80 mm and place it on top of the roof section so that the edge of the roof is along the middle of the rubber hinge.

Fix the hinge to the roof using four small roofing felt tacks or heavy duty staples.

Return to the box assembly and place it, front uppermost, with the top facing towards you.

Offer up the newly hinged roof and fix the other half of the rubber hinge to the back again using four felt nails or heavy duty staples.

Now all we need is a way of keeping the roof closed. You could use screws but these take a long time to undo when you need to clean out the box in the autumn – particularly when they start to corrode. A simple locking method is to knock two netting staples into the roof and front respectively, but not all the way in so they leave two holes.

Thread some string or a piece of wire through the two loops and fasten the roof down securely.

Step 3: siting your bird box

Now you’ve built your bird box you need to place it in location that will be appreciated by the birds. Hung on a north facing wall or in a shady tree the box will remain cool as the weather warms in the spring.

Make sure you also put it out of reach of any predators, particularly cats, for obvious reasons but also position away from bird feeders as the nesting pair will be constantly chasing the feeding birds away from their territory!

The ideal height for fixing is somewhere between 2 and 5 metres. Be careful on those ladders!

The fixing method will vary depending on the location – screws for house and garage walls or wire loops for fixing to tree trunks and branches.

After fixing retire to the kitchen for a well earned cup of tea!

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