How to make a bird’s home a happy one


- Credit: PA

Planning to do your bit for National Nest Box Week? Experts offer 9 tips to make sure you get the best nest boxes.

If you are planning to put up a nest box during National Nest Box Week

and beyond, the British Trust for Ornithology and the RSPB are warning

that, while some boxes provide a perfect breeding cavity for birds,

others are far from ideal.

You may be tempted to buy eye-catching brightly coloured nest boxes and

quirky types shaped like caravans, farmhouses, eggs and windmills, but

Most Read

the RSPB warns that attractive and elaborate bird boxes aren’t

necessarily safe or effective for nesting birds.

So, what should we be going for? The BTO offers the following


1. Make sure it’s insulated

Only choose a box made from an insulating material such as wood or a

special waterproof wood/concrete compound like Woodcrete, used for the

National Nest Box Week ‘official’ box.

2. Avoid metal and ceramics

Don’t choose a box made from dense materials like metal or ceramics as

the interior can become too hot or too cold for chicks to survive. Nest

boxes with metal roofs retain too much heat and can have fatal effects

for baby birds on warm, sunny days. Metal and plastic nest boxes also

suffer from condensation causing baby birds to get damp and cold.

3. Choose a type with thick walls

To provide insulation and be durable, the walls of wooden boxes should

be at least 15mm thick. Wooden boxes can be safely treated on the

outside with a preservative provided it is non-toxic and water-based. A

box made from cedar, oak or beech will far outlive one made from

softwood such as pine.

4. Check the hole size

Choose a box with a 32mm entrance hole as this is the ideal size for all

small hole-nesting birds such as sparrows and tits. Choose a smaller

26mm hole only if you want to restrict the box to blue tits.

The box should not be too small inside as birds may lay fewer eggs in

smaller boxes. The internal floor area should at least 130 square cm (20

square inches).

6. Avoid perches

Perches are not necessary and may even act as a foothold for squirrels

or weasels as they reach into the box to grab eggs and chicks.

7. Maintain easy access

A good box should provide easy access for human observers who wish to

record the contents and to clean out the disused nesting material at the

end of the season.

8. Place them strategically

The ideal height for a small-hole type nest box is between 1m and 5m

above the ground with a clear flight path. Care must be given to make

sure the box isn’t easily accessible to predators.

There are different kinds of nest boxes for different species of bird.

Cavity nesting birds like nest boxes with entrance holes, and the size

of hole will depend on the target species.

For example, blue tits prefer boxes with a small hole (25mm), Starlings

on the other hand would need slightly larger holes (45mm). Other birds

like open-fronted nest boxes, such as robin and spotted flycatchers.

9. Avoid...

Steer clear of brightly coloured nest boxes. The more inconspicuous they

are, the better. Make sure they are not made from flimsy materials as

many boxes fall apart when any weight is put inside.

Don’t let them be too shallow as young birds could leave prematurely by

falling out, and don’t let them be too deep as young birds may have

problems getting out when they are ready to leave.

National Nest Box Week, a joint project between the BTO and Jacobi Jayne

& Co, runs from February 14-21. For details visit