Building a DIY Swift Box for a Community Project

Why Swifts Need Our Help

The swift is one of Britain’s most iconic summer visitors, but it is in serious trouble. The UK swift population has fallen by more than half in recent decades, and the species is now on the Red List of birds of conservation concern. The main reason is loss of nest sites. Swifts traditionally nest in cavities under the eaves of old buildings, in church towers, and in gaps behind roof tiles. When roofs are repaired, soffits replaced, or new homes built without those little gaps, swifts return from Africa to find their nesting places gone. They are site-faithful, often returning to the same roof year after year. A community project to build and install DIY swift boxes can replace some of those lost sites — but only if we work together. One box on one house is rarely enough. Swifts are colonial, so clusters of boxes across a street or village give them the best chance.

Choosing Materials and Tools for a Weatherproof Swift Box

Swifts need a box that is dark, dry, and durable. Start with 18mm exterior-grade plywood or marine ply. Avoid pressure-treated timber, creosote, and any wood treated with toxic preservatives — these can harm birds. You will also need galvanised screws (about 40mm), exterior wood glue, and a water-based exterior wood stain in a dark colour. Dark boxes absorb warmth, which swifts appreciate in cool British summers. For tools, gather a saw, drill, screwdriver, clamp, tape measure, pencil, safety glasses, and gloves. A jigsaw or a 65mm x 30mm oval hole cutter will make the entrance. If you are running a community build, buy materials in bulk from a local timber merchant. That keeps costs down and ensures everyone uses the same safe, untreated wood.

Building the Box: Dimensions and Assembly

Use these internal dimensions: 30cm wide, 35cm deep, and 15cm high. Cut the floor, back, and front panels to 30cm x 35cm. Cut two side panels to 35cm x 15cm. The front panel needs an oval entrance hole measuring 65mm wide by 30mm high, positioned about 5cm down from the top edge. Drill a few 6mm drainage holes in the floor corners. Assemble the box with exterior wood glue and galvanised screws, pre-drilling to avoid splitting. Add a roof panel that overhangs the front and sides by 5cm for weather protection. Make one side or the roof removable with screws so you can inspect the box in winter. Sand any rough edges, then apply two coats of water-based stain to the outside only. Never paint or varnish the inside, and do not add nesting material — swifts prefer a bare wooden floor. A simple box like this costs very little and takes about an hour to build once the panels are cut.

Siting Your Swift Box Safely

Siting is everything. Swifts need to drop from the entrance to gain speed, so place boxes 5 to 7 metres above ground with a clear flight path. Avoid trees, wires, or walls within 10 metres of the entrance. The ideal aspect is north or east, which prevents overheating in direct summer sun. South and west-facing walls can become lethal in a heatwave. Mount boxes under the eaves or on a gable end using sturdy galvanised brackets. For community buildings — village halls, schools, churches — always get written permission from the owner or council. Working at height is the biggest risk. Use a ladder safely: secure it, follow the 1-in-4 rule, and have a spotter. If you are unsure, hire a qualified installer. Aim to have boxes up by late April, before swifts return in early May. Once installed, leave them up year-round. Swifts will prospect new sites in July and August, and young birds return in following years.

Getting Neighbours Involved

A community swift project is as much about people as birds. Start by holding a build workshop in a garage, village hall, or school. Bulk-order materials, make a template for the entrance hole, and pair experienced DIYers with beginners. Map any existing swift nests in your area — listen for the screaming parties on summer evenings. Then aim for clusters: three to five boxes per building, repeated across several neighbouring houses. Knock on doors, explain the decline, and offer to help build or site a box. You can also use swift call playback to attract prospecting birds. Play recordings from a speaker near the boxes during May, June, and July, morning and evening. Keep the volume low and stop by 9pm out of respect for neighbours. Involve local schools: children can sand, stain, and decorate a removable exterior panel. A “swift street” with a few shared signs can turn a few boxes into a real neighbourhood project.

Monitoring, Maintenance, and Patience

Check your boxes in winter, between November and January, when swifts are in Africa. Look for signs of use: dark droppings, feathers, or a shallow nest cup. A cheap endoscope camera can help you peer inside without opening the box fully. Record first arrival dates, number of birds entering, and any successful fledging. Report your sightings to your local biodiversity records centre. Be patient. It can take two to three years for swifts to find a new box, and sometimes longer. Young swifts spend their first year or two prospecting, so keep boxes up and do not move them. Repair leaks, tighten screws, and re-stain the exterior every few years. Never disturb the box during the breeding season from May to August. If you find a grounded swift, contact a wildlife rescue immediately. Above all, enjoy the reward: the sight of a swift slipping into your box on a summer evening is one of the best sights in British birdwatching.