A perfectly built box in the wrong place stays empty. A modest box in the right place fills every year. Siting is the part people spend least time on and it matters more than almost anything else.
Aspect, and why north east is the standard advice
The most repeated piece of nest box guidance in Britain is to face the entrance somewhere between north and east, and there is a genuine reason behind it.
Facing south means the box takes full afternoon sun, and a small wooden box in July sun gets hot enough to kill a brood. Facing west means it takes the prevailing wind and driving rain, since our weather predominantly comes from the south west. North to east avoids both: cooler through the afternoon, sheltered from the worst of the rain.
If you cannot manage that aspect, deep shade from a tree or a wall achieves much the same result and is a reasonable substitute.
Height
Between two and four metres suits most small species, which in practice means higher than head height and lower than a ladder is comfortable.
Open fronted boxes for robins and wrens are the exception and sit lower, typically one to two metres, but they must be in dense cover such as a hedge or a climber rather than on an exposed wall.
Higher is generally safer from cats. Lower makes cleaning easier. Two and a half to three metres is the usual compromise.
The flight path
Birds approach a box directly and need a clear run at the entrance. A box tucked behind dense foliage, or with a branch immediately across the hole, will be rejected however good it is otherwise.
Stand where a bird would approach and look at the hole. If you cannot see it cleanly from several metres away in the open, neither can they.
At the same time, a box in the middle of a bare wall with no cover anywhere near it is exposed. The ideal is a clear approach with cover nearby but not immediately in front.
Tilt
A slight forward tilt, so the entrance points marginally downward, keeps driving rain out of the hole. Not much, just a few degrees. Tilting backwards funnels water in, which is a common accidental error when a box is screwed to a leaning fence post.
Distance from feeders
Further than most people put them. A nest box next to a busy feeding station is a stressful place to raise chicks, with constant traffic from other birds and the territorial disputes that come with it.
Several metres between the two is better, and different sides of the garden better still. Feeders also attract predators, which is the second reason for the distance.
Spacing between boxes
Most garden birds are territorial in the breeding season and will not tolerate a neighbour of the same species close by. Two blue tit boxes on the same fence will usually result in one being used and one ignored.
Space boxes for the same species well apart, ideally out of sight of each other. Boxes for different species can be closer, since they compete less directly.
Cats, squirrels and corvids
The three main garden threats, and each has a countermeasure.
For cats, height and the absence of a convenient launching point matter most. Avoid siting a box directly above a fence top, a shed roof or a thick branch that a cat can work along.
For grey squirrels, a metal hole plate around the entrance prevents them enlarging the hole by gnawing, which is exactly what they do.
For magpies and jays, depth below the hole is the defence, which is why the 125mm minimum matters, along with not providing a perch.
Fixing it up
On a tree, use aluminium nails or a strap rather than steel nails or wire, both of which damage the tree as it grows and can be dangerous if the tree is later cut. On a wall or fence, a screw through the batten at the back is straightforward.
Check the fixing each autumn when you clean the box, since a season of weather loosens things.
Where our boxes suit
Our seagrass bird boxes and the carved tree trunk face houses are decorative shelters rather than certified nest boxes, so the siting rules above apply with less urgency. They still benefit from a sheltered aspect and a position out of the worst weather, and they still want to be somewhere birds are comfortable approaching.
Our guide to bird box hole sizes covers what makes a box suitable for a brood.
Questions people ask
Which way should a bird box face?
Between north and east. Facing south means full afternoon sun which can overheat a box, and facing west takes the prevailing wind and rain. Deep shade is a reasonable substitute.
How high should a bird box be?
Two to four metres for hole nesting species, with two and a half to three metres the usual compromise between cat safety and ease of cleaning. Open fronted boxes sit lower, in dense cover.
How far should a bird box be from a feeder?
Several metres at least, and different sides of the garden if possible. Constant traffic near a nest is stressful, and feeders attract predators.
Can I put up two bird boxes near each other?
Not for the same species, which are territorial in the breeding season. Space same species boxes well apart and ideally out of sight of each other. Different species can be closer.
How should I fix a box to a tree?
With aluminium nails or a strap rather than steel nails or wire, which damage the tree as it grows and are hazardous if it is later felled.
