Our ultimate guide to nest boxes

We all need a safe place to live and for wildlife it’s no different. One of the biggest causes of wildlife declines is a lack of suitable habitat. 

In addition to providing insect-attracting plants on which they can feed, we can give birds a helping hand by offering cosy bird boxes and nest sites. Whatever the size of your outdoor space, this is a really easy way to help the nature on your doorstep.

It seems so simple, but providing nest boxes is one of the easiest ways to help birds in your outside space. Putting out bird food is great, but if birds don’t have access to nesting sites, they won’t have anywhere to raise the next generation. It’s also key that the nest sites are nearby to foraging locations, where they can find plenty of invertebrates without leaving the nest for too long.

Different birds prefer different-sized nest boxes and entrance holes – it’s all about safety and shelter. A hole that is just about big enough for them to squeeze through means nothing larger can reach them, and they are also well protected from anything the weather can throw at them.

The problem is that our gardens and balconies can be rather short of natural holes. Our trees are often not old enough to have developed the nooks and crannies that wildlife craves, and we tend to patch up holes in our buildings.

Luckily, it’s quick and easy to add artificial homes in the form of nest boxes. Why not get your whole street involved? Chat to your neighbours and see if they’d be keen to make your street a Sparrow Street or Swift Way by putting multiple boxes up at once. You could organise a day to put up all the nest boxes together.

If you like a spot of carpentry, you can knock up your own nestboxes, and we have several templates for you to follow. But if you’re not Handy Andy, there are plenty you can buy, starting with our wide selection in the RSPB shop.

Putting a nestbox up allows you to watch some fascinating bird behaviour up close. Here are a few things to look out for.

Tits are regularly seen hammering away at the entrance hole of a nestbox. This is probably a form of display by the male, rather than an attempt to enlarge the hole.

Later, the female will also peck vigorously: natural holes may have all the surrounding bark chipped away. This may help her to judge how soft the wood is and whether the hole will provide a safe, predator-proof home in which to raise her brood. Blue and Great Tits will also hammer at the inside of a box or nest hole, perhaps as a form of display.

Nuthatches leave tell-tale signs of their residence in a nestbox. They peck at the entrance hole, deliberately enlarging it. They then plaster the edges of the hole with mud, making sure the hole a perfect fit for their bodies.

Pied Flycatchers are fast nest builders. They have been known to take over a nestbox in use by another bird, and build their own nest and lay eggs on top of a fresh clutch – or even live chicks – within days.

Many birds roost in nestboxes, especially during a cold winter night. These roosts are often shared, with the birds packing together for extra warmth. The record number of birds found in one box is 61 Wrens.

There’s so much joy to be had from watching wildlife move into the accommodation you’ve provided. And with many boxes these days coming with mini-cameras so you can live stream the action, there’s every chance to turn it into a daily drama come spring.

Birds aren't the only things that like to enter nest boxes. Predators and insects may also take up residence.

Birds such as House Sparrows and Starlings often take over nesting holes used by tits. Most tits are able to defend a box successfully, provided that the intruder cannot get inside. A hole size of 25mm will exclude larger species. Do not fix a perch on the front of any box, as this will encourage intruders. Birds don't need a perch in order to use the box.

By putting up nestboxes with different-sized holes, you'll cater for a variety of species. Please remember that House Sparrows and Starlings are in serious decline and may need help even more than the tits. Do not place sparrow boxes too close to ones intended for other birds, especially House Martin colonies. 

Nestbox predators include cats, squirrels, rats, mice, stoats, weasels, woodpeckers and, in the case of open-fronted boxes, members of the crow family. As predators mainly hunt early in the morning, most people are unaware of their presence.

A metal plate fixed around the entrance hole may deter woodpeckers and squirrels, while spiky vegetation, such as gorse or rose clippings above and below the box will give some protection against most mammals, such as cats.

You can find the RSPB-approved CATWatch cat deterrent in the RSPB shop.

Bees, wasps or earwigs will, on occasions, take over nestboxes. As many of the insects are useful food for birds, it is best to leave them alone. Insects often move in after birds have finished nesting, and any young found dead are likely to have died of other natural causes.

It is not unusual for the same type of insect to return to the box in subsequent years. Leave that box in situ as a bug box, and put up another nest box a few feet away. It is rare for both to be lost to insects.

This activity counts as the Build a Birdbox Wild Challenge activity if you are doing it as a family group.

This is a Nature On Your Doorstep activity which can also be completed as part of Wild Challenge. Want to take on the challenge and go for Gold? Each action you take for nature brings you a step closer. Here’s how.