An amendment to make swift bricks mandatory in new housing in England will be debated in the House of Lords this week in what campaigners call a “golden opportunity” for the government to halt wildlife decline. The change to the controversial levelling up bill is being tabled by the Conservative peer Zac Goldsmith, who resigned from government over Rishi Sunak’s “apathy” towards environmental issues. “There aren’t that many conservation solutions as easy as this one,” said Goldsmith. “The cost of adding swift bricks to new builds is so tiny, relative to the cost of the build itself as to be almost immeasurable, and the impact on species that are perilously close to extinction would be vast.” The swift brick is an unobtrusive hollow brick that provides a home for cavity-nesting species including the endangered red-listed house martin, starling and house sparrow, as well as other small birds and invertebrates. Britain’s population of the migratory swift – whose “screaming” over house roofs is an evocative sound of summer – declined by 60% between 1995 and 2020. Since then, numbers have dropped further, from 59,000 breeding pairs to an estimated 48,000. The loss of nesting sites – particularly with energy-efficiency measures sealing up old roofs – is a factor in the birds’ decline along with the decline of flying insects they feed on. Fitting swift bricks to all new homes received cross-party support when it was debated in parliament in July after a government petition was signed by 110,000 people, but the government has reiterated its desire to leave any requirement for their installation to local authorities. Only five of 455 planning authorities in England ask that house builders install the bricks in new homes, in line with best practice. According to Murray Davidson, the vice-chair of the Association of Local Government Ecologists, leaving it to local authorities is “neither an effective nor efficient way to implement an urgent conservation measure”. A number of Tory MPs and leading Conservatives have spoken in support of mandatory swift bricks alongside some major housebuilders. Josie Cadwallader-Hughes, the sustainability director of Thakeham, said: “Thakeham support the amendment for an industrywide commitment to delivering support for this red-list species. As a housebuilder, Thakeham recognise the opportunity we have to support nature recovery through the landscape-led master planning, but also within the homes we build. Universal bird bricks are a simple way that we can support swifts.” The writer and campaigner Hannah Bourne-Taylor, who set up the petition, said: “This amendment is a golden opportunity for the government to honour its own commitments to halt biodiversity loss by 2030. Following unanimous cross-party support from MPs, the future of swifts in Britain, birds dubbed our ‘icons of summer’, is in the hands of peers, who have the chance to safeguard not only these irreplaceable birds, but our connection to the nature on our doorsteps.” The Conservative peer Lord Randall of Uxbridge, who is supporting the amendment, said: “Hannah’s campaign has been amazing but now it’s down to us in parliament to legislate for this. Such an easy win for nature so it’s crunch time to show that we care about nature and in particular the ‘devil’ birds.” Goldsmith added: “Their natural nesting sites have all but vanished, and this tiny step would rectify that on a meaningful scale. And who wouldn’t want to have swifts nesting in their homes?”