Why Position Matters More Than the Box Itself

A well-built nest box in the wrong spot is little better than no box at all. Birds are surprisingly choosy about where they raise a brood, and the difference between a box that sits empty for years and one that fledges a family every spring often comes down to placement. Get the location right and you will be rewarded with the comings and goings of blue tits, great tits, sparrows, robins and even the occasional nuthatch or treecreeper.

There are four things to think about before you drill a single screw: shelter from the weather, protection from predators, a clear approach for the incoming bird, and the correct height for the species you hope to attract.

Shelter From Wind and Rain

In the UK, our prevailing winds come from the south-west for much of the year, so a box facing between north and east is usually the safest bet. A south-west-facing box will take the brunt of every storm that rolls in off the Atlantic, and driving rain can soak through the entrance hole, chilling eggs and chicks.

A little tilt goes a long way, too. Angle the box very slightly forward — just a few degrees — so that rainwater runs off the roof rather than sitting on it or dribbling inside. Avoid mounting boxes where water will collect, such as directly beneath a broken gutter or a leaking downpipe.

• Face the box between north and east as a general rule.
• Shade it from the strongest midday and afternoon sun, especially on a south-facing wall.
• Keep the entrance clear of dense, wet foliage that stays damp after rain.

Keeping Out the Sun

Overheating is a real risk in a warming climate, and a box that bakes in full sun can reach lethal temperatures on a July afternoon. Small chicks cannot regulate their body heat well, and a nest box facing the sun from mid-morning onwards can become an oven.

If you only have a sunny spot available, choose a position that catches shade for part of the day — behind a deciduous shrub or on the shaded side of a wall. Deciduous trees are ideal because they are bare in winter, letting light through, but leafy in summer when the shade is most welcome. A wall-mounted box in full southern sun should ideally be moved or given some form of shelter.

You can also help by choosing a box with a thicker roof or a slightly overhanging lid, which keeps the interior cooler.

Height and the Right Species

Height matters, and the right height depends entirely on the bird. Putting a box too low exposes it to cats; too high and you may struggle to check or clean it safely.

• Blue tits and great tits: 2–4 metres up, often on a tree or wall, with a 25–32 mm entrance hole.
• House sparrows: 2–4 metres, often in loose colonies of two or three boxes close together.
• Robins and wrens: lower down, around 1–2 metres, and they prefer an open-fronted box hidden in ivy or a climbing plant.
• Nuthatches and treecreepers: higher, 3–5 metres, ideally on a mature tree trunk.
• House martins: under the eaves, 2–4 metres, with a special cup-shaped nest.

If you are not sure what you will attract, a standard 32 mm hole box at around 2.5–3 metres is a solid all-rounder for tits and sparrows.

Out of Reach of Predators

Cats are the biggest threat to low boxes, but squirrels, magpies, jays and even woodpeckers will raid a nest given the chance. A few simple measures make a big difference.

• Mount boxes at least 2 metres up, and further from any branch, fence or wall a cat could launch from.
• Use a metal plate around the entrance hole to stop squirrels and woodpeckers enlarging it.
• Fit a predator guard — a deep wooden or metal tunnel around the hole — to keep paws and beaks out.
• Avoid placing a box directly beneath a bird table or feeder, where spilled food attracts rats and magpies.

Positioning the box so the entrance faces away from a nearby perch also helps: predators cannot sit and watch the comings and goings, and neither can they reach straight in.

A Clear Flight Path and Good Neighbours

Birds like an easy approach. Make sure there is a clear, unobstructed line of flight to the entrance so the parent bird can land, feed the chicks and leave again without battling twigs or netting. Trimming back vegetation in front of the hole — but not the cover around the box — gives them the confidence to use it.

Think about neighbours, too. Tits are territorial and will not tolerate another pair nesting too close, so keep tit boxes at least 10 metres apart. Sparrows, by contrast, are sociable and will happily nest in a cluster, so three boxes on the same wall can work well for them.

Finally, once a box is up, leave it alone. Check it in autumn after the breeding season for a clean-out, but resist the temptation to peek during spring — disturbance at the wrong moment can cause a pair to abandon the nest entirely.