Time to get your nest boxes ready for the new year
Now is the time of year to renovate old nest boxes or set up new ones. Nest boxes that were used by breeding birds last year need to be checked for damage, repaired, cleaned out, disinfected, repainted and got ready for the coming nesting season.
During the early part of the winter, empty boxes may have been used as dormitories by Wrens or colonised by Garden Snails. They may be in a state of disrepair and in need of some attention. If previously used, they may contain parasites.
Designs for making nesting boxes are readily available on the Internet. Wood at least 15mm thick is ideal. Old floor boards can be put to good use. Recycled or new wood needs to be weather-proofed by painting it with a brown or green preservative stain. The stain must be non-toxic, so creosote is not an option.
Blue Tits and Great Tits are among the commonest colonisers of nest boxes. Both are hole nesters so the entrance hole to the box can be drilled to suit them. A hole of diameter 25mm will allow Blue Tits to enter and exit but will prevent bigger birds from using the box.
Great Tits need a hole size of 28mm and House Sparrows need one of 32mm. If squirrels are common nearby they may enlarge the hole by gnawing the wood to get at eggs or chicks. In that case, the hole should be drilled in piece of metal and the metal nailed over the hole in the box.
Birds like Robins and Blackbirds that are not hole nesters need a box with a large front opening. A tit box is fine on an open, bare wall but an open-fronted box needs to be concealed in deep, shaded cover.
All boxes need to be positioned about 2m off the ground in a location that cannot be accessed by cats. Boxes also need to be protected from the weather. Facing north or east is best with the box tilted forward to throw off rainwater.
To ensure that the residents have some degree of privacy, nest boxes in gardens need to be located at least 10m from bird tables, feeders and other nest boxes.
Even when everything appears to be right to the human way of thinking, birds may not colonise a nest box for reasons best known to themselves. In that case, move the box every year until success is achieved.