London HogWatch

What do we do?

London HogWatch was established in 2016 to identify the locations of the main hedgehog populations in Greater London. By increasing our understanding of hedgehog abundance and distributions, we can better inform future conservation management strategies and help combat the decline of hedgehog populations in London.

So far, HogWatch has conducted major surveys of some of the most important green spaces supporting hedgehog populations, in addition to exploring new locations where there was deficient information on hedgehog presence and absence. More specifically, we have identified substantial hedgehog ‘hotspots’ - in northeast London including in the Highgate and Hampstead area, and others in the southwest Barnes and Twickenham area, in addition to several smaller populations across North and South London.

Why Hedgehogs?

Hedgehogs have recently been classified as ‘vulnerable to extinction’ in the UK with one study estimating numbers to have declined by 46% in the last 13 years. Multiple factors may be interacting to produce this effect, including habitat loss and fragmentation, use of pesticides and agricultural chemicals, road traffic, and potentially the increasing badger population.

Historically, hedgehogs have been an integral element of both urban and rural biodiversity in the UK but have declined dramatically in recent years. Evidence suggests that this decline has been particularly severe in rural areas, highlighting the significance of urban hedgehog populations for conserving this species. Hedgehogs occur in several areas across Greater London, but our current understanding of these remaining populations is poor. For us to take effective conservation measures, a greater knowledge of their distribution and population sizes in London is required.

How do we do it?

Between April and October, we carry out systematic camera trapping surveys across Greater London in a range of different habitats, including parks, gardens, and private green spaces. This allows us to collect data on the presence and absence of hedgehog populations. Camera trapping also means we can monitor the occurrence of other London wildlife populations that might impact hedgehogs. Our analyses of the data enable us to address knowledge gaps about the occurrence, size, and connectivity of hedgehog populations. With this information, we can detect where habitats have become fragmented, for example we have identified roads as a major threat for London’s hedgehogs, which prevent them from accessing otherwise suitable habitats.

London HogWatch’s ability to conduct surveys is only achievable with the kind support of our funders and collaborators. We work with a variety of groups including councils, local environmental groups, charities, and companies. We are particularly grateful for the support of the British Hedgehog Preservation Society, HogWatch's core funder, and The City of London Corporation who have funded our 2025 Highgate Woods camera-trap survey and the creation of this Zooniverse project. Without them this work would not be possible.

HogWatch continues to expand every year and has currently carried out surveys in 60% of all London Boroughs and put out around 4,000 camera traps across London. The map below shows London boroughs in green which have been surveyed since the project began in 2016, each year the scope of our work continues to expand into new areas.

Public Engagement

Our work across various London Boroughs, would not be possible without the help of numerous volunteers from community groups, residents, and societies. HogWatch is constantly undertaking camera trap surveys that involve large numbers of volunteers, providing the opportunity for members of the community to get out into nature and help wildlife local to them. Volunteers help us set up cameras in London’s parks and green spaces and take cameras home to conduct their own garden survey to monitor potential hedgehog activity. These garden surveys are an important addition to our data as gardens can act as important refuges for hedgehogs in highly urbanised areas.

Citizen Science: Our work combines citizen science data obtained from various external charities such as, NBN, GIGL and, PTES. We have used this information to better understand hedgehog habitat use across the capital which can be found here. We have also recently conducted our own historical knowledge survey to understand the present and past distributions of hedgehogs. If you would like to fill out our short questionnaire, the website can be found here (https://tinyurl.com/ysxezjw4).

School’s education: The iconic status of hedgehogs, along with the conservation technology that underpins this work, provides an ideal platform for supporting schools’ educational activities. Throughout the programme, we have made several schools visits (both in primary and secondary schools), supported work experience placements for secondary school children and delivered talks to school visitors at ZSL.