National Hedgehog Monitoring Programme

A pioneering new three-year pilot project – the National Hedgehog Monitoring Programme (NHMP) – has been launched.

For the first time, this will enable robust estimates of hedgehog populations in different habitats across the country, show how these are changing year on year, and, in time, give a national estimate of Britain’s hedgehog population. The new project utilises sophisticated, cutting-edge artificial intelligence (AI), which is a world-first in hedgehog conservation.

Led by wildlife charities The British Hedgehog Preservation Society (BHPS) and People’s Trust for Endangered Species (PTES), in partnership with Nottingham Trent UniversityZSL’s London HogWatch, Durham University and MammalWeb, and largely funded by Natural England, this unique combination of AI, trail cameras and home-based volunteers will produce crucial insights into the factors causing hedgehog populations to plummet, and enable conservationists to implement practical conservation measures to try to reverse the decline.

How does it work?

The NHMP uses trail cameras to capture images of hedgehogs (and other wildlife) in different habitats, including urban parks, private gardens, woodlands and farmland. AI algorithms sort all the images captured, minimising the numbers of blank or human images, and maximising the number of animal images for home-based volunteers – known as ‘spotters’ – to identify. Once the images are classified, a team of analysts can produce vital population numbers and information. The algorithms have been developed by Conservation AI, machine learning specialists based at Liverpool John Moores University.

Volunteers needed to get involved

Volunteers from all corners of the UK are needed to make the project a success and can take part from the comfort of their own homes. Last year, trail cameras were placed at 13 different sites across the country, from Dorset to Glasgow. 30 trail cameras were placed at each site and were left in situ for a month, generating thousands of images. The species in these images need to be identified. The process is straight-forward: simply look through a sequence of images, tag which species you see, and continue!

Dr Henrietta Pringle, National Hedgehog Monitoring Programme Coordinator at People’s Trust for Endangered Species explained:

“For the first time in the history of hedgehog conservation we’re using AI to open up new opportunities, which is extremely exciting. Previous studies have estimated hedgehog populations, but there has never been a rigorous nationwide survey of them – until now.”

We know hedgehogs are struggling, especially in the countryside, but before we can put practical conservation measures in place we need to understand where they are and why they’re declining. This is the first study where populations are measured year after year, in the same location, which will produce vital data and allow us to identify those at risk, which in time will hopefully help us to reverse the decline. The results will also allow us to see regional and habitat differences, and identify what factors impact them in different places, which will not only be fascinating but also incredibly useful for their long-term conservation.”

Fay Vass, CEO of The British Hedgehog Preservation Society added:

“Everyone loves hedgehogs, but we recognise that not everyone is in a position to help them in the wild. Becoming a ‘spotter’ for the National Hedgehog Monitoring Programme is a fantastic way for everyone to get involved. Now, those with mobility issues, who don’t have a garden or perhaps are away studying at university or college, can help from the comfort of home. Helping hedgehogs has never been easier or more accessible, so we really hope people from all walks of life take part.”

The NHMP team, with the help of a pilot group of volunteers, has started the enormous task of checking the images from the 13 sites surveyed in 2023. Hedgehogs have been spotted at six of them so far, and many other interesting species, such as tawny owls, stoats and red squirrels have also been seen.

Over the three years of the NHMP’s pilot, the team will place cameras at an increasing number of sites across Britain. The ambition is to have surveyed 40 sites by the end of the trial, which should produce enough data to derive a more accurate estimate of the numbers of hedgehogs in the different habitats surveyed, and give a robust national estimate. Going forward the existing sites will be monitored annually, and new sites added.

To sign up and become a ‘spotter’, visit


*The State of Britain’s Hedgehogs 2022 report, published by BHPS & PTES, revealed that rural hedgehog populations have declined by between 30 and 75% across different areas of the countryside since 2000.

You can see the hedgehog data (more than 361,000 records) we hold on the NBN Atlas here.


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