10 Years On: How the Duchy of Cornwall’s Nest Boxes Are Bringing Birds Back

A decade after launching a bold effort to support wildlife, the Duchy of Cornwall is celebrating 10 years of success in integrating built-in nest boxes across its developments. The long-term project, created in partnership with the RSPB, has seen 1,289 nest boxes installed—and the latest survey shows they are being used more than ever.

A Decade of Progress

Since the initiative began, the Duchy has been embedding nest boxes directly into the walls of new homes and buildings in Nansledan and Tregunnel Hill in Newquay, Trevethow Riel in Truro, and Poundbury in Dorset. The approach ensures that urban development contributes to biodiversity rather than harming it.

Over the years, the number of nest boxes occupied has steadily increased, with the most recent survey showing that 49% were in use in 2024—up from 42% the previous year. The evidence suggests that as the boxes become a more established part of the landscape, birds are becoming more likely to use them.

Wildlife Making a Comeback

The long-term success of the project is seen in the return of species that have struggled across the UK. In 2024, the most commonly recorded nests included:

• House Sparrows – 163 confirmed nests
• Starlings – 86 nests
• House Martins – 69 nests

These birds have faced significant population declines in recent decades. According to the British Trust for Ornithology, House Martins and Starlings have declined by 44% and 54% respectively since 1995, while House Sparrow numbers have fallen by 7%.

Ben Murphy, Estate Director at the Duchy of Cornwall, highlighted the importance of the project in tackling these declines:

“When we started this initiative with the RSPB over 10 years ago, our aim was to help address the decline in wild bird populations as part of our plans for boosting biodiversity by pioneering the use of built-in nest boxes in new developments.

“With thanks to the RSPB for their guidance in the design and installation of these boxes, we’re delighted to see year-on-year increases in the rate of occupancy, and the extent to which the wider housebuilding industry is taking on board the importance of supporting wildlife in this way.”

Looking Ahead

As the Duchy marks 10 years of success, it is expanding its efforts, with a commitment to installing one nest box per home at its new 2,500-home development in South East Faversham, Kent. Other biodiversity measures introduced across Duchy developments include hedgehog highways, bee bricks, and broader habitat restoration efforts.

At Nansledan in Newquay, the Duchy is forecasting a 24% increase in biodiversity net gain by the time the development is completed.

Dr Thais Martins, a biodiversity expert who has led The Big Duchy Bird Box Survey since 2019, praised the long-term impact of the initiative:

“It’s hugely encouraging that the total percentage of nest boxes showing signs of use continues to increase and now stands at more than 600 across these Duchy sites. As the developments continue to mature and create new habitats, we expect to see even higher levels of occupancy in the years ahead.”

The success of the Duchy’s nest box work has helped shape wider industry standards, with a British Standard for built-in bird boxes introduced in 2023. The Duchy is also a founding member of the Future Homes Hub ‘Homes for Nature’ initiative, sharing its experience with other developers.

As more developments embrace this approach, the impact could extend far beyond the Duchy’s estates. To follow the latest findings and get involved, The Big Duchy Bird Box Survey has a dedicated Facebook page.