Press release: World-first combination of trail cameras, AI and volunteers used to find out robust hedgehog population estimates for the first time

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  • The ground-breaking new National Hedgehog Monitoring Programme uses sophisticated, cutting-edge AI technology to help hedgehogs, a world-first in hedgehog conservation.
  • For the first time the results will provide robust estimates of hedgehog numbers in different parts of the country, how these are changing year on year, and in time, a national estimate.
  • Volunteers across the UK are needed to identify images of hedgehogs (and other wildlife) online as part of the project, and can do so from the comfort of their own home.
  • The results will give crucial insights into what’s causing hedgehog populations to decline so rapidly (between 30 and 75% in rural areas since 2000*). Once this is understood, practical conservation measures can be implemented.

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 University, ZSL’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.

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 maximizing 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 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! Free training and ID guides are available online. To find out more and to sign up, visit

Dr Henrietta Pringle, National Hedgehog Monitoring Programme Coordinator at People’s Trust for Endangered Species explains: “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 adds: “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.

–  ENDS –

For high res images, interview requests or further information, please contact Adela Cragg:

T: 07532 685 614


Notes to Editors

Available for interview

  • Dr Henrietta Pringle, National Hedgehog Monitoring Programme Coordinator at People’s Trust for Endangered Species (PTES) and The British Hedgehog Preservation Society (BHPS)
  • Fay Vass, CEO, The British Hedgehog Preservation Society
  • Nida Al-Fulaij, CEO, People’s Trust for Endangered Species
  • Other partners, as required.

Supporting quotes from partner organisations

Philip Stephens, Professor of Ecology at Durham University, says: “This project is a great example of how people from all over the country can work together to improve the state of our biodiversity. Durham University’s new Biodiversity Strategy commits us to maintaining and enhancing the natural environment, improving habitats for a wide variety of wildlife and plants. As a Gold Award Hedgehog Friendly Campus, it’s fitting that we should have run one of the initial surveys on campus and it was fantastic to have a large group of students from our hedgehog society involved. We are already looking forward to this year’s surveys, and to playing an important role in the National Hedgehog Monitoring Programme.”

Russell Hill, Director at MammalWeb, says: “MammalWeb’s aim has been to work with diverse groups of people to support nationwide camera trap studies of wild mammals. It’s fantastic for our platform to be part of this important collaboration. We’re excited that this project is harnessing integrated machine learning from our colleagues at Conservation AI, supporting participants to process the large volume of images the project will collect. We’re looking forward to working with new ‘trappers’ and ‘spotters’ to generate the critical data needed to understand the status of hedgehogs in the UK and to develop strategies for their conservation.”

Dr Claire Howe, Senior specialist for Mammals at Natural England, says: “Hedgehogs are one of Britain’s most loved wild animals, but we know surprising little about these fascinating creatures and the reasons behind their recent worrying declines. Natural England is proud to support this project which is a fantastic opportunity for anyone to become a ‘citizen scientist’ and help to bring hedgehogs back to our gardens and our countryside. Working collaboratively together, we will take a crucial step towards assessing the status of our hedgehog populations to enable strategic conservation efforts to ensure a brighter future for this iconic species.”

Dr Richard Yarnell, Associate Professor in Ecology in Nottingham Trent University’s School of Animal, Rural and Environmental Sciences, said: “NTU is delighted to be a leading partner in the programme, which will continue our extensive research into the conservation of Great Britain’s mammals. As well as providing vital information on the status of hedgehogs, the programme will also provide urgently needed monitoring information for many other mammals across the UK, and help evidence whether the government’s species abundance targets are being met.”

Dr Marcus Rowcliffe, Senior Research Fellow at ZSL, says: “ZSL takes a leading role in global animal population monitoring. This evidence is crucial to identify areas where species are at risk, directing conservation efforts to support wildlife. Utilizing novel camera trap technologies, ZSL is excited to contribute to a UK-wide hedgehog monitoring initiative, aiming to understand and address the decline of this vital species as well as others, ensuring their persistence across the country.”

About The British Hedgehog Preservation Society (BHPS)

  • The British Hedgehog Preservation Society (BHPS) is a registered UK Charity, founded in 1982, dedicated to helping & protecting hedgehogs native to the UK (Erinaceus europaeus). Through our campaigns, advocacy and educational projects we work to raise awareness of the practical steps we can take to help reverse the decline of hedgehogs in the wild, improve their welfare and safeguard the future of this much-loved animal. We also fund research that provides important new insights into the conservation and welfare of hedgehogs. 
  • Visit and follow BHPS on FacebookXInstagram and LinkedIn

About People’s Trust for Endangered Species (PTES)

  • PTES, a UK conservation charity created in 1977, is ensuring a future for endangered species throughout the world. We protect some of our most threatened wildlife species and habitats, and provide practical conservation support through research, grant-aid, educational programmes, wildlife surveys, publications and public events.
  • PTES’ current priority species and habitats include hazel dormice, hedgehogs, water voles, noble chafers, stag beetles, traditional orchards, native woodlands, wood pasture and parkland and hedgerows.
  • PTES has Species Champions for two of its priority species: for hedgehogs The Rt Hon Chris Grayling, MP for Epsom & Ewell and for water voles The Rt Hon Hilary Benn, MP for Leeds Central and Chair of the Brexit Select Committee.
  • Visit and follow PTES on Facebook, Twitter, Instagram, YouTube & LinkedIn.

About Durham University

  • Durham University is a globally outstanding centre of teaching and research based in historic Durham City in the UK.
  • We are a collegiate university committed to inspiring our people to do outstanding things at Durham and in the world.
  • We conduct research that improves lives globally and we are ranked as a world top 100 university with an international reputation in research and education (QS World University Rankings 2024).
  • We are a member of the Russell Group of leading research-intensive UK universities and we are consistently ranked as a top 10 university in national league tables (Times and Sunday Times Good University Guide, Guardian University Guide and The Complete University Guide).
  • For more information about Durham University visit:

About MammalWeb

  • MammalWeb is a “citizen science” platform intended to collate, validate and curate camera trap data that can inform us about the distribution and ecology of mammals for scientific, policy and management purposes. Initially established as a collaboration between Durham University and Durham Wildlife Trust, MammalWeb aims to enable and expand citizen science camera trapping to address the information deficit on the status and ecology of UK and European wild mammals. In doing so it engages a community of citizen scientists, ranging from school children to enthusiasts, researchers, and the general public, to deploy cameras, and help classify the images and, thereby, aims to enhance the connection of people to nature with benefits for health and wellbeing.
  • Visit, follow MammalWeb on Facebook, X, Instagram and YouTube, and subscribe to our newsletters

About Natural England

  • Natural England is the government’s adviser for the natural environment in England. We help to protect and recover nature. We conserve and enhance the natural environment for its intrinsic value, the wellbeing and enjoyment of people, and the economic prosperity it brings.

About Nottingham Trent University

  • Nottingham Trent University (NTU) received the Queen’s Anniversary Prize for Higher and Further Education in 2021 for cultural heritage science research. It is the second time that NTU has been bestowed the honour of receiving a Queen’s Anniversary Prize for its research, the first being in 2015 for leading-edge research on the safety and security of global citizens.
  • The Research Excellence Framework (2021) classed 83% of NTU’s research activity as either world-leading or internationally excellent. 86% of NTU’s research impact was assessed to be either world-leading or internationally excellent.
  • NTU was awarded The Times and The Sunday Times Modern University of the Year 2023 and ranked University of the Year in the Whatuni Student Choice Awards 2023. It was awarded Outstanding Support for Students 2020 (Times Higher Education Awards), University of the Year 2019 (Guardian University Awards, UK Social Mobility Awards), Modern University of the Year 2018 (Times and Sunday Times Good University Guide) and University of the Year 2017 (Times Higher Education Awards).
  • NTU is the 5th largest UK institution by student numbers, with approximately 40,000 students and more than 4,400 staff located across five campuses. It has an international student population of 7,000 and an NTU community representing over 160 countries.
  • Since 2000, NTU has invested £570 million in tools, technology, buildings and facilities.
  • NTU is in the UK’s top 10 for number of applications and ranked first for accepted offers (2021 UCAS UG acceptance data). It is also among the UK’s top five recruiters of students from disadvantaged backgrounds and was the first UK university to sign the Social Mobility Pledge.
  • NTU is ranked the second most sustainable university in the world in the 2022 UI Green Metric University World Rankings (out of more than 900 participating universities).

About ZSL and London HogWatch

  • Founded in 1826, the Zoological Society of London, is an international conservation charity, driven by science, working to restore wildlife in the UK and around the world; by protecting critical species, restoring ecosystems, helping people and wildlife live together and inspiring support for nature.
  • London HogWatch, a project by ZSL, monitors urban biodiversity to address the decline in hedgehog populations in Greater London. It aims to understand the abundance and distribution of hedgehogs, informing conservation strategies using advanced camera trapping surveys. ZSLs cutting-edge camera-trapping techniques which have advanced population estimation, have contributed to the NHMP methodology.
  • Visit for more information.

Header image credit Neil McIntyre

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