Swifts' decline: how can Britons help these remarkable birds?

The Guardian

17-06-2025

The swift (Apus apus) is an acrobatic aerial bird, a remarkable sprinter and endurance flyer that rarely touches the ground. When these sickle-winged birds do come down – after several years in perpetual flight, even sleeping midair – it is to nest in the eaves of roofs across Europe after spending winters in sub-Saharan Africa, migrating 7,000 miles (11,000km) every year. They are celebrated by nature-lovers, artists and poets as they race through city skies on long summer evenings, filling the air with their screaming calls.
The fastest bird in level flight (top speed: 69mph/111kph), they feed on airborne insects. Swifts are in trouble because of steep declines in insects, but also because they are losing traditional nesting sites. Swifts once nested in caves and hollow trees but moved into buildings hundreds of years ago. Modern insulation, particularly in roofs, removes the crevices and cavities where they have nested for centuries.
Grim. Swift populations slumped by 66% between 1995 and 2022 in Britain and have continued a rapid downward trend. Since the last count of 59,000 breeding pairs, the population this summer is set to be just 40,000 pairs. In five years' time, there could be fewer than 25,000, unless action is taken.
Declines are not so pronounced across continental Europe despite similar insect declines. Countries such as Germany and France appear to have retained more nesting sites in old buildings than in Britain, where few buildings constructed after 1944 can accommodate swifts.
A swift brick is a hollow brick which slots into the brickwork of new or old homes, providing a cavity where swifts can nest. The bricks have also been found to help other cavity-nesting birds, including the rapidly declining red-listed house martin, house sparrow and starling. Other species including blue tits, great tits, nuthatches and wrens will also nest in the bricks.
Swift bricks are made by brick manufacturers large and small, and typically cost about £35. There is a British Standard for them and some developers are already fitting them to new homes.
Three years ago, the writer and bird lover Hannah Bourne-Taylor launched a campaign to oblige every new home to be fitted with a swift brick. When in opposition, the UK Labour party supported the 'swift brick amendment', first tabled by the Conservative peer Zac Goldsmith, to do this in England. Now in government, Labour is resisting attempts by its own backbench MP Barry Gardiner to insert a swift brick amendment into the controversial planning and infrastructure bill.
Labour is reluctant to impose additional regulations on housebuilders as it attempts to address the UK's housing affordability crisis with a big push for new homes. Nearly 30 housebuilders have voluntarily agreed to install one brick for every new home built. Labour's latest move is to suggest adding swift bricks to national planning policy guidance so that all England's local planning authorities insist on them for new homes. But Bourne-Taylor says this won't guarantee more swift bricks, because many planning authorities lack the resources to ensure planning conditions are met. A recent study found developers, who make multi-billions in profits, were not providing 75% of the nesting boxes stipulated in planning permissions.
'By refusing to mandate swift bricks, the government is making it clear to their voters that they do not care about nature because this would be the easiest nature recovery action, ever,' said Bourne-Taylor. 'Loads of people have told me that they will never vote Labour again because of how the government have acted on swift bricks.'
Wooden swift boxes are widely available and are suitable for swifts, provided they can be installed at least 4.5m above ground and not on a south-facing aspect, because this is too hot for the nesting birds. Retrofitting an integral brick is more expensive but slightly better because it provides a cooler space and will last longer than a wooden box.
Even if a swift box is ignored by swifts, it will be a boon to other birds. And there are many other ways to help swifts. The Swift Local Network unites swift lovers across Britain. Local groups rescue fallen birds and protect existing nesting sites: talking to neighbours who have swifts in their roofs raises awareness if roofs are renovated.
The government's commitment to insulate Britain will be welcomed by all environmentally minded voters, but this makes it more crucial than ever that swift bricks are integrated into all new homes. Campaigners are emailing the housing secretary, Angela Rayner, to let her know.
Site-faithful swifts sometimes take a while to discover new nesting opportunities. If house sparrows first take up residence, this is good news because swifts often seek out nesting spaces where they see sparrows – they are a signal for swifts that there are good homes here!
Some people play swift calls from a window close to a new nestbox to attract curious swifts when they first arrive back in Britain in May. This can help, but usually only in areas that already have swift populations.