Investigating the behaviour of rehabilitated hedgehogs

Mammal Society council member Dawn Scott is an expert in mammal ecology and conservation. Dawn is Head of the School of Life Sciences at the University of Keele.  Twitter @ProfDawnScott.

Together with PhD student Kate Davies, Dawn is currently leading a conservation study on the post release behaviour of rehabilitated hedgehogs. We asked Dawn to tell us more about it.

Why study hedgehogs?

As we have seen in the Mammal Society’s Red List of Britain's Mammals, hedgehog populations across Europe have declined by 50% over the last 10 years in the countryside, and about 30% in urban areas; there now could be fewer than one million left in the UK. Hedgehogs are also the most frequently admitted mammal to wildlife rehabilitation centres in the UK, with numbers admitted appearing to be increase, despite the population decline.  

What is the particular focus of your study?

Many hedgehogs are admitted to rehabilitation in the Autumn, with a significant proportion kept in rehabilitation overwinter due to health or weight concerns. The majority of those admitted are thought to be juveniles, or young of the year, and therefore have had less experience of living in the wild prior to admission, compared to adults. The hibernation period in the UK typically lasts from November to April after which rehabilitated hedgehogs are released back into the wild, ideally at the point where they have been found, but sometimes this Is not possible and a new suitable location needs to be found.  Previous research by the team has shown that release during winter can be undertaken in the correct conditions, with no effect on the survivorship of the animals. However, they also found that the post hibernation Spring period is a high-risk time for hedgehogs. To further inform how we can help increase hedgehog survival and breeding success, the team set out to investigate rehabilitated hedgehog behaviour after being released from rehabilitation in the Spring.   

The aim of successful wildlife rehabilitation is to release the individual in a condition that allows them to survive as equally as well as their wild counterparts, for example, with the ability to recognise appropriate food sources and higher risk environments, as well as being able to select mates and reproduce and as a result continue to contribute to the population. Despite this there have been relatively few studies on the post release behaviour and survivorship of rehabilitated wildlife. Where this has been investigated research has found that, as well as experiencing stress in captivity, reintroduction stress can occur, as well as increased mortality risks and altered ranging behaviour upon release. 

How could your findings help with hedgehog conservation?

This research is being carried out in collaboration with a local hedgehog rescue centre and seeks to investigate how hedgehogs that have been overwintered in care fare when released in the Spring. The research will use GPS tags to study the fine scale behavioural patterns of both rehabilitated and wild hedgehogs to help answer the studies overarching question - How does overwinter captivity effect the post release behaviours of rehabilitated hedgehogs compared to wild hedgehogs?  It is hoped that the research will contribute to rehabilitation practices and help us to understand how we can maximise the chances of successful reintroduction to the wild. 

The research has received a favourable ethical opinion from Keele University’s Faculty of Natural Sciences Research Ethics Committee and is carried out under a Science, Education and Conservation licence issued by Natural England. GPS tags are an approved method for studying animal behaviour, they weigh less than 3% of the body weight, are attached onto the spines (not skin) by glue and animals are re-caught and tags removed after 7 days. Animals are aloes marked with coloured tubing to monitor the population longer term.

The research forms part of a wider study on wildlife rehabilitation currently being led by Dawn and Kate. We will be watching with interest and will bring you updates as we receive them.

BBC Springwatch covered this story on 10 June 2021. If you have access to iPlayer you can watch it by clicking on the link - the item begins at around 33 minutes https://www.bbc.co.uk/iplayer/episode/m000wvzs/springwatch-2021-episode-11

If you spot a hedgehog in your garden or when you’re out and about, whether it is dead or alive, please remember to record it on the Mammal Mapper app. Your records are vital in helping us to form a true picture of the status of Britain’s mammal species.

To read more about hedgehogs visit the species hub https://www.mammal.org.uk/species-hub/full-species-hub/discover-mammals/species-hedgehog/.

Are hedgehogs at risk in your area? Find out more about hedgehog hotspots at https://www.mammal.org.uk/science-research/hedgehog-hotspots/

Donate to the Mammal Society's #HogsOnRoads appeal here.