RESIDENTS living at Duchy of Cornwall developments are being encouraged to take part in this year’s nest box survey.

The annual Big Duchy Bird Box Survey, which runs from May to August, monitors the use of built-in nest boxes across Duchy developments including Nansledan and Tregunnel Hill in Newquay, Trevethow Riel in Truro, and Poundbury in Dorset.

The long running initiative forms a key part of the Duchy’s wider commitment to support biodiversity and reconnect communities with nature.

The Duchy has worked with the RSPB for more than a decade to integrate nest boxes into new homes and buildings, helping to address the decline of cavity-nesting birds across the UK. The so-called 'swift bricks' resemble normal bricks or blocks but are hollow inside.

The initiative, which celebrated its 10th anniversary last year, is part of the Duchy's broader approach to sustainability, which includes habitat creation, green spaces, and measures to support wildlife across its estate. It aims to install an average of one nest box per new home built.

The government has consulted on making swift bricks a requirement in new developments, and the Scottish Parliament passed a law in January.

The Duchy’s project has the backing of conservationist, author and campaigner Hannah Bourne-Taylor, who is campaigning for swift bricks to be mandatory in building regulations.

She said: “Swift bricks are paramount to the prevention of swifts becoming extinct in Britain. The housing sector must take responsibility for the only category of birds reliant on buildings to survive and follow the Duchy’s leadership when it comes to swift brick installation to secure the only permanent nesting habitat for these iconic birds.

“The Big Duchy Bird Box Survey is such an important survey because it shows that swift bricks really do work.

“If you build it they will come. The more people take part in the survey, the better because the more evidence collected, the stronger the case for installation which is urgently necessary if we are to save these birds.”

The annual Big Duchy Bird Box Survey’s latest survey results show a total of 1,497 nest boxes installed across Duchy developments, an increase of almost 200 on the year before, with 684 boxes, almost 46 per cent, showing signs of use during the 2025 breeding season.

House Sparrows remained the most common species, with 159 confirmed nests, followed by House Martins 93 and Starlings 71.

Significantly, swifts were recorded nesting in Duchy-built boxes for the first time, with six nests identified across Tregunnel Hill and Poundbury. The hope now is that numbers will grow and swifts also move into the other sites.

Dr Thaís Martins, a biodiversity expert who leads the annual survey, said: “Seeing swifts begin to nest in the Duchy’s boxes for the first time is incredibly exciting. These birds are famously slow to adopt new nesting sites, so this was always something we expected would take time.

“What this shows is that by putting the right infrastructure in place and being patient, we can create real opportunities for species that are in long-term decline.”