Searching for Shrews Press Release

For immediate release 15/12/22

• The GWT shrew is a new non-native species in Britain and might become invasive, affecting native shrews
• DNA sampling is being planned to be able to answer where it originated from
• Mammal Society and MammalWeb are calling for increased monitoring of small mammals, in particular shrews, in Britain
• Since the first press release, another likely GWT shrew has been identified in Nottinghamshire from photographs taken of a dead specimen earlier this year. Indicating that monitoring of shrews should be at national extents.

In September 2022, the Greater White-toothed (GWT) shrew was discovered in Great Britain by Ian Bond, from a specimen caught by Melissa Young’s indoor cat. This new non-native mammal, found in the Sunderland area, was confirmed via a DNA test undertaken by Ecotype Genetics and Swift Ecology Ltd.

At present, the GWT shrew is not known to be invasive in Britain but, as a new non-native species, it has the ability to become invasive. The GWT shrew is known to outcompete the pygmy shrew in Ireland and there is a possibility that the GWT shrew will negatively affect, or completely displace our pygmy shrew.

“When the species was first found in Ireland in 2007, we thought that it could be a positive addition and maybe act as a new and plentiful prey source for birds of prey and other carnivores.” said Allan McDevitt of the Mammal Society. “However, we soon realised that the native pygmy shrew had completely disappeared whenever the GWT moved into an area. Obviously, we are concerned about similar problems occurring in Britain.”

The GWT shrew is native to Europe, North Africa and some of the Channel Islands. Although the origins of the shrews found in Sunderland are currently unknown, they could have been imported from Ireland or the European continent. DNA sampling is being planned to be able to answer this question.

With this in mind, the Mammal Society and MammalWeb are calling for increased monitoring of small mammals, in particular shrews, in Britain. There is a need to confirm the GWT shrews' presence in the wild, find out how far it has spread, and determine whether it is affecting the abundance of pygmy shrews.

The Mammal Society and MammalWeb are currently promoting ways to record the presence of all small mammals, so we can monitor GWT shrew distribution and any changes to pygmy shrew abundance. We have suggested using camera traps, taking photos of sighted shrews, alive or dead, and checking owl and bird of prey pellets for shrew remains. Ad hoc sightings - ideally with photos - can be recorded using the Mammal Mapper app. Camera traps can be modified to record small mammals, and all resultant footage submitted to the MammalWeb platform.

"Camera traps placed in baited boxes and modified with close-focus lenses can yield amazing footage of small mammals," said Philip Stephens, one of the founders of MammalWeb. "These sensors remain active 24-hours a day, yielding footage that enables experts to identify which species are where, and how they affect each other."

Since the GWT shrew in Sunderland was first identified a number of shrew records have been reported. Recently, a photograph of a dead shrew in Nottinghamshire, submitted via the Mammal Mapper app, was reviewed by independent experts and confirmed to be a highly likely GWT shrew. This record is over 200km away from the initial GWT shrew sighting and highlights the importance of vigilance and widespread recording of small mammal species across national extents. 

Frazer Coomber Science Officer at the Mammal Society finishes "The recording of any mammal species is important as it helps us to understand their current distribution and population and how these change over time. Small mammals are under-recorded, and it is essential to collect baseline data on them. We need to know their current distribution, population and species assemblages so that we can understand the effect that GWT shrews could have on our native species. Recording mammals using the Mammal Society’s Mammal Mapper app is straightforward and anyone with a smartphone can submit a record. The ability to take photographs, alongside each record, helps to ensure species recorded can be verified accurately. So, even if you are unsure what species it is, please photograph it and report it as a small mammal."

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ENDS

For further information please contact:

Sophie Webb (usual working hours 09:00 – 17:30 Mon – Fri)

T: 02380 010983

E: pr@themammalsociety.org

Further information;

• On the continent it is known as the House Shrew because of its association with human habitation.
• It is an invasive species in Ireland where it is estimated to be spreading at 5km/year, an astonishing distance for a small mammal. Wherever it has spread in Ireland it appears to have led to the complete disappearance of the Pygmy Shrew, but it is unclear what its ecological implications would be in Britain, where the ecological landscape is more complex.
• Learn more about this species here.
• Learn more about the Searching for Shrews project here.
• Download Mammal Mapper here. 
• Learn about small mammal camera boxes here.
• Click here for the original press release.
• Click here for the open access paper on the GWT shrew discovery.
• Photo available on request.
• Any non-native species sightings can be recorded online through MammalWeb, iRecord or on the Mammal Mapper
• See the Mammal Society’s position statement on invasive mammals here.

About the Mammal Society:

One in four of our native mammals is threatened with extinction, and many others are in decline. With Britain now recognised as one of the most nature-depleted countries in the world, urgent action is needed. The Mammal Society is working to give our wildlife a better future by:

• Keeping a constant watch on the conservation status of our mammals and making this information freely available
• Making conservation more effective by providing guidance on what to do and where to do it
• Educating the public and professionals about wild mammals, training people to survey them, and sharing the latest research
• Working in partnership to restore native mammal populations and re-establish functional ecosystem

The Mammal Society is the only charity with an interest in all British mammals. The Mammal Society’s conservation work is supported through the generosity of our supporters. A list of our current and past projects can be found here. To join the Mammal Society visit our website. Recent Mammal Society publications include: The State of Mammals in Wales and the Atlas of the Mammals of Great Britain and Northern Ireland

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. Goals include:

• Enabling and expanding citizen science camera trapping to address the information deficit on the status and ecology of UK and European wild mammals;
• Engaging a community of citizen scientists, ranging from school children to enthusiasts, researchers, and the general public, to deploy cameras, and help classify the images;
• Facilitating the use of data gathered for scientific, policy and management purposes;
• Enhancing the connection of people to nature and its benefits for health and wellbeing.

MammalWeb was set up in collaboration between Durham University and Durham Wildlife Trust. It is run by MammalWeb Limited a not-for-profit company under the direction of representatives from Durham University, Durham Wildlife Trust and the National Wildlife Management Centre.

You can contact MammalWeb by emailing info@mammalweb.org.