At first, it is hard to spot. A small hole in the eaves is often all that can be seen. It’s only on closer inspection that a hollow brick can be discerned, slotted neatly into a wall. Inside might be a pair of nesting swifts that have travelled thousands of miles from Africa to the UK.
At Manthorpe Building Products’ factory in Derbyshire, it takes just under a minute to produce a single swift brick that could provide a safe haven for generations of these migratory birds. Granules of recycled plastic are put into an injection moulding machine and, moments later, the separate parts of the brick come out, before a worker snaps them together.
Manthorpe has already made 20,000 bricks. Dozens of workers in hi-vis vests group around futuristic-looking machines, producing a wide range of building products from loft hatches to drains. Yet it’s the swift bricks that have proved a surprise hit, with demand steadily increasing year on year, says the company’s managing director, Paul Manning.
Things could be about to get busier. A petition to make swift bricks compulsory in all new housing in the UK has more than 100,000 signatures and will be debated in parliament on 10 July. It will be an uphill battle, though. In its response to the petition, the government made clear that it “considers this a matter for local authorities depending upon the specific circumstances of each site”.
Campaigners argue that these bricks are desperately needed amid the relentless decline of swifts in the UK. The species was added to the “red list” of endangered birds in 2021 after its population fell by 58% from 1995-2018.
Swifts are celebrated for their endurance, spending 10 months of the year entirely airborne. They feed on insects and mate in the sky, they drink by gliding over smooth water and bathe by flying slowly through rain. To sleep, they close one eye and half of their brain at a time. Swifts only land to breed, returning to the same nest site for a few short months to raise their young.
However, renovations in old buildings are closing up the holes in walls where they used to nest and new buildings block them out, too. Plummeting insect populations are also a factor in the species’ decline but nest loss is a problem with a simple solution: swift bricks and boxes.
Bricks are the preferred option as they slot discreetly into a wall, offer a cooler environment for the birds, do not require any maintenance and should last the lifetime of a building. The first swift bricks were designed about 30 years ago, but since then there has been a huge rise in demand with dozens of models now available. Prices vary between £15 and £176 and many are compatible with UK brick sizes, meeting the requirements of the British Standard for internal built-in nest boxes for swifts and other wildlife.
Developed in conjunction with the RSPB and the house building industry, the brick being produced by Manthorpe has a grippy finish in the entrance tunnel to help swifts land, a concave dish to make nest building easier, as well as internal channels for drainage, and tabs to aid bricklaying. Mike Challinor, the development and technical director at Manthorpe, tested a range of 3D prototypes, from a binocular-shaped model to one with an external ledge, before settling on the final design. “The brick had to work for the housebuilder as well as the swifts because they wouldn’t be used otherwise,” he says.
Ibstock is another swift brick manufacturer that has seen demand grow, with 7,000 units sold so far. The design of the slim clay box evolved after the discovery that some bricklayers were fitting them upside down. “If that happens, the swift chicks may not be able to get out of the hole,” says Ian Downie, Ibstock’s national specials champion. Ibstock began spraying “top” on the boxes with a picture to prevent this happening, while a nesting ledge was also added inside “to prevent the eggs from rolling out”.
Swift bricks are usually installed in new buildings or during major renovations, but it is possible to retrofit them into an existing wall. Action for Swifts founder Dick Newell designed the S Brick for this purpose and has sold 3,000 of them since 2020. As well as supplying individual swift enthusiasts, the organisation recently sold 30 bricks to a Cambridge project after it forgot to install nest sites. Newell laments that “new houses exclude all wildlife” and estimates that we need at least 250,000 swift bricks and boxes in place to restore swift numbers lost in the last 25 years.
“The great advantage of swift bricks and boxes is that they can work just as well in inner city areas with very little green space as anywhere else,” says Dr Guy Anderson, the RSPB’s migratory birds programme manager. “Swifts can travel pretty long distances to find their insect food – all they need is a nest site.” Even if swifts don’t make a home in them, the bricks can be used by other species, including house martins, starlings, great tits and house sparrows.
Examples of swift brick victories include redevelopments of housing estates, such as the Windmill Estate in South Cambridgeshire where more than 250 swift bricks and boxes have been installed since 2009. Barratt Developments has installed more than 4,000 swift bricks in new housing developments since 2016 – with plans for 7,000 by 2025 – and there are at least 68 local authority and neighbourhood plans with wording for nest box or swift brick provision, according to the Swift Local Network group. The RSPB says that since Brighton and Hove city council introduced a planning condition requiring new buildings to include swift bricks, at least 130 of them have been installed across the city.
Some campaigners argue, however, that this provision is too patchy and that a national strategy is required. Hannah Bourne-Taylor, who started the petition to make swift bricks compulsory across the UK, says that such a policy could help the government meet its biodiversity targets and is a “no-brainer” in terms of its simplicity and effectiveness. “Swifts are our closest wild neighbours and the poster children of biodiversity,” she says. “If they lose, we lose.”
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