Weekend Projects – Nest Boxes

Wednesday 11 July 2018

The numbers of garden birds have declined over recent years and wildlife charities, such as the Royal Society for the Protection of Birds (RSPB) and the British Trust for Ornithology, actively encourage the feeding of wild birds and the provision of nest sites. A visit to their websites will provide much more information than I can convey in this short article. You don't need a country estate to give a helping hand to our feathered friends, a carefully sited nest box in a small suburban garden or city yard can provide a nesting site for a whole variety of bird species depending upon the design and location.

Attracting birds to your garden not only helps the birds, but also provides you with the pleasure of watching their activities from close range. It has other advantages too as many species feed on insects, aphids and other invertebrate garden pests. Different species have different nesting requirements, some are hole nesting species, while others prefer an open fronted nest box. In this article I make two boxes, the first has a 25mm hole suitable for blue tits or coal tits, while the other has an open front for robins or wrens. Correct location of the box is also important. The sizes of holes and openings and the locations preferred by a range of common species is shown in the chart below, which is based on information from the RSPB website.


You don't need to be too fussy about what wood you use, but avoid treated timber which may contain harmful chemicals and man-made boards which will not withstand the weather. I used a single 2.4m redwood (Pinus sylvestris) board left over from another project to make both boxes. Whatever you use, make sure it is nice and square. One end of my board was cupped so I ran it through the planer/thicknesser first.


I used hand tools to make the first box. Begin by measuring and marking out the two sides of the box. While this is not fine cabinet making, accurate measuring and marking are still important to ensure a quality end result, so take care to get the sides exactly the same.


The top of the front and the back of the lid will need to be angled to fit snugly, so set a bevel gauge to match the angle of the top of the sides. This will be used to get the correct angle on the front and lid. If you don't have a bevel gauge you could make a cardboard template.


Using a sharp cross cut saw, cut out the sides. Make sure the board is supported on both sides of the cut. My trestle is the same height as my workmate and has a central slot for the saw to ensure this support.


Use the bevel gauge to mark out the angles of the front and the top on the edge of the board and square lines down both faces. Plan your cuts so that only one angled cut is needed, forming the top of the front and the back of the lid.


With the work now supported in a vice or workmate, carefully make the angled cut, sighting down the marked lines to keep the cut true. The back and base are straightforward square cuts.


Mark the centre of the access hole in the front of the board, 125mm from the bottom and centred between the sides. With the front held securely in a vice and backed with a piece of scrap to prevent breakout, drill a hole of a suitable size for the species you wish to attract. I used a Forstner bit, but a flat bit or auger bit would be suitable.


The box will be nailed together as glued joints will prevent any water that gets into the box from draining away. Pre-drill the nail holes to prevent splitting.


Order of assembly is not critical, but I find it easier to nail the sides to the base first. Support the opposite end of the sides with an offcut and work on a solid surface.


If using wire nails, drive the heads of the nails below the surface of the wood with a nail punch. You could use galvanised or stainless nails to avoid rusting. Continue the assembly by nailing the front to the sides and base making sure everything is a good fit, especially where the top will rest on the front and sides to avoid gaps.


Before nailing the backboard in place, drill countersunk holes at the top and bottom for the mounting screws.


I decided to fill the nail holes with a two-part resin filler. This is not strictly necessary, but will help prevent the nails from rusting and prolong the life of the box. A coat of water based, pet and wildlife friendly wood stain may be applied to the outside of the box, but do not treat the inside.


The top of the boxes with full or high fronts needs to be hinged for access. The hinge can be as simple as a strip of rubber glued in place. In my case, I used an offcut of brass piano hinge.


The top of the nest box is kept in place with a simple hook-and-eye fastener.


The components for the second box were cut out using a sliding mitre saw. This is a much quicker method and makes for accurate angled cuts.


A groove must be cut in the back of this box into which the lid will fit. This can also be done with the mitre saw or you could use a router or cut it by hand. If necessary, tidy up the groove with a bevel edged or paring chisel.


Assembly is the same as for the first box, except that the lid is this time nailed in place. Here you can see how it fits into the groove in the backboard.


Don't forget to drill a couple of holes in the bottom of the box for drainage.


Here are the finished boxes ready to be positioned.


The first box was positioned 2.5m up on a north east facing garage wall, where I hope it will attract blue tits and coal tits.


The second box, designed to suit robins, was located on a fence post in a sheltered corner of the garden partially concealed by ivy.