Why siting matters as much as the box

A well-made nest box in the wrong spot is little more than garden furniture. The same box screwed to a sun-baked south wall and to a sheltered east-facing fence can produce wildly different outcomes — one cooks its occupants, the other fledges a brood of blue tits. Birds are choosy about where they raise young, and giving them the conditions they would look for in a natural hole is the single easiest way to improve your chances of a tenant.

Face it between north and east

British weather arrives overwhelmingly from the south-west, and a box facing that way takes the worst of it. Driving rain soaks the entrance, water seeps in around the roof, and a wet nest is a cold nest. A south-facing box has the opposite problem: strong afternoon sun can push internal temperatures uncomfortably high, particularly in a small box with thin walls, and overheating is a genuine cause of chick deaths in a warm June.

So the sweet spot sits anywhere from north round to east. A north-facing box stays cool and dry all summer. An east-facing box catches gentle morning sun, which warms the box early and helps dry the condensation that builds up overnight from the birds' own breath — often the best of the two. If your only option is a south or west wall, look for a spot in the deep shade of a shrub, a fence panel or the building's own shadow, and consider a box with thicker, better-insulated walls.

One detail often overlooked: the box should sit perfectly upright or tilted very slightly forward, so the roof overhangs the entrance and rain runs away from the hole. Never tilt it back.

Match the height to the species

Height is where a little knowledge pays off, because different birds nest at very different storeys. As a rule, mount boxes two to four metres up, high enough to be out of reach of a curious cat but low enough to inspect and clean safely.

• Blue tits and great tits: two to four metres on a tree, wall or shed, with a clear flight path to the hole.
• House sparrows: two to four metres, often under the eaves or on a gable wall. They will happily nest in loose colonies, so several boxes close together can work well.
• Starlings: three to five metres, ideally on a tall tree or building, with a larger 45 mm entrance hole.
• Robins, wrens and spotted flycatchers: one to two metres, tucked into ivy, honeysuckle or a dense shrub, with the box partly hidden. These are the species most likely to use an open-fronted design.
• Nuthatches: two to four metres on a mature tree trunk, with a metal plate around the hole to stop them enlarging it.

Keep your distance from feeders and tables

It is tempting to hang a box beside the feeder so you can watch the comings and goings from the kitchen window. Resist it. Feeding stations are crowded, noisy places, thick with droppings, spilt seed and the predators that spilt seed attracts. A pair trying to settle will be disturbed constantly, and a box within a metre or two of a busy table is often abandoned.

Aim for at least five metres, and ten if your garden allows. Avoid siting a box directly above or beneath a feeder, where debris and droppings fall and birds fly at speed past the entrance. It is also worth keeping tit boxes well apart from one another — five to ten metres is sensible — because blue and great tits defend a small territory around the nest and will squabble over a box that is too close to a neighbour's.

Shelter, predators and the view out

Think about what the bird sees from the entrance hole. It wants a clear approach, but not an exposed one. Dappled light is ideal: some sun through the day to keep the box warm, screening from the worst of the wind and rain, and no convenient ledge — a fence rail, a low branch, a shed roof — within easy pouncing distance of a cat.

Check above the box as well. A branch or shelf directly overhead gives squirrels and magpies a place to sit and work at the entrance, and cats will use it too. Fix the box securely and vertically to a tree or wall using a strap or an aluminium nail rather than several nails driven into the trunk, and fit a metal predator plate around the hole — it protects against squirrels, woodpeckers and the occasional determined great tit.

Small tweaks that tip the odds

• Put boxes up by late winter. Birds prospect for nest sites from January onwards, and early February is ideal for tits.
• Add a thin layer of dry wood shavings as a base — never hay, which holds damp and harbours parasites.
• Leave the box alone once nesting begins. Resist the urge to open it and check; disturbance can cause desertion, and later chicks may fledge early.
• Clean out between September and November, once the last brood has gone, and scrub with boiling water rather than chemicals.
• Keep a simple record of what nests where and when. After a season or two you will know exactly which aspect and height your garden's birds prefer, and can add more boxes accordingly.