October is the best month to clean out any bird boxes you have. Remove any nesting material and unhatched eggs and if possible, take the box down and pour boiling water into it to kill parasites. Obviously, carrying a kettle full of boiled water up a ladder is not safe, so please don’t attempt this treatment unless you can get the box down first! Put the box back when it’s dry or take the opportunity to relocate it, if you think it’s in the wrong place (see below for advice on location). I realised that one of my robin boxes has no vegetation around it until summer, so I’ll be moving that to an evergreen tree this month.
You might think that your bird boxes won’t be used again until spring, but birds often roost in them over the winter. Why not put up new nest boxes now so the more vulnerable birds have a warm shelter during the cold nights coming up? You can buy bird boxes at many garden centres, pet shops and online or you can make your own using the instructions below. Whichever you choose, read the whole of this article first to make sure you don’t install a bird box that is vulnerable to predation or is unlikely to be chosen as a nesting site.
In general, nest boxes should be fixed facing between north and south-east. Do not place them in a sunny spot because the chicks will overheat. Put the box above head height, in a quiet part of your garden, not easily accessible to cats
Making your own bird box can be very satisfying, but before you embark on this fairly simple-looking project, consider whether you have the right tools and materials. The wood for the box needs to be 15mm thick or more – ideally recycle something rather than buying new timber. You’ll need galvanized nails or screws and a specialized drill bit for making the entrance hole.
Think about which species you hope to attract to your new home. Some are much more likely to use man-made nest boxes than others. Which species have you seen in your garden or nearby? There’s no point designing a box for birds that are not in your area.
The table below gives appropriate dimensions for species that most commonly use nest boxes. All measurements are in mm.
|Species||A x B x C||D||E|
|Blue Tit & Coal Tit||150 x 150 x 200||25||130|
|Great Tit||150 x 150 x 200||28||130|
|House Sparrow||150 x 150 x 200||32||130|
Robins and wrens prefer an open-fronted design but as this style leaves the chicks very vulnerable, the box must be sited in thick vegetation, where cats and other predators can’t get to it. The measurement of E (base to open hole) in this case needs to be 100mm. Other species that readily use artificial homes include swifts, swallows and house martins. If you are lucky enough to have those birds in your neighbourhood, pre-moulded nests can be bought to place under the eaves of your house.
Having said all that, I have had blue tits nesting in the great tit box and great tits using the house sparrow box, so the wildlife doesn’t always pay attention to the rules! So get planning and get those boxes up this autumn to give the birds a chance to get used to them before they choose a place to nest in spring. Good luck!