Guidance document
A guide to identifying the small mustelids of Ireland
Published
Celebrating 50 years with our biggest Irish stoat study yet: The Irish Stoat Citizen Science Survey 2023-2025.
As Vincent Wildlife Trust (VWT) celebrates its 50th anniversary, and with this week marking both National Volunteer Week and Biodiversity Week in Ireland, we are thrilled to celebrate these milestones with the completion of our largest Irish stoat study to date — the Irish Stoat Citizen Science Survey.
The Irish stoat (Mustela erminea hibernica) is a unique subspecies, found only on the island of Ireland and the Isle of Man. Despite its protected status across the island of Ireland, it remains one of our least understood mammals.
Small, fast and highly secretive, the Irish stoat presents a major challenge to wildlife researchers. Unlike other members of the mustelid (weasel) family, such as otters or pine martens, stoats leave behind few obvious field signs like footprints, fur or scats (carnivore droppings). This, combined with their wariness of traps, makes monitoring extremely difficult.
Very little is known about the Irish stoat’s overall distribution, which is why our recent citizen science survey marks an important step forward. By gathering observations from volunteers across both the Republic of Ireland and Northern Ireland, we have been able to build a clearer picture of this charismatic species’ distribution.
In this blog, we look back at our work on the Irish stoat, explore insights from the latest citizen science survey, and share what’s next in our efforts to understand this unique subspecies.
A look back
Hair tubes
VWT’s first Irish stoat study was launched in 2010, which aimed to find a reliable, non-invasive method of detecting this elusive species (McAney, 2010). With funding from The Heritage Council and Galway County Council, the study tested whether baited plastic tubes fitted with sticky patches, known as ‘hair tubes’, could collect hairs suitable for DNA analysis.
A vital part of the project was the involvement of 50 dedicated volunteers from across County Galway, who set up more than 600 hair tubes in their local areas. From April to October, tubes were placed along hedgerows and stone walls across 50x10km grid squares.
Once the tubes had been in place for up to two weeks, the volunteers retrieved any hairs that had stuck to the glue patches inside. These samples were carefully stored in sterile containers and sent for DNA analysis at Waterford Institute of Technology (now South East Technological University).
The results were encouraging. Irish stoat DNA was detected at 20 sites, 15 in east Galway and 5 in the west, confirming the presence of stoats in a range of habitats, including roadside hedgerows, field margins and traditional stone walls.
Although a successful non-invasive way to detect stoats, this method is only suitable at a small and local scale for several reasons. It takes quite a lot of time to bait 600 tubes with chicken wings and, in the beginning, it was a challenge to find enough chicken wings but eventually a local butcher came to the rescue.
At the time, Galway County was one of the few local authorities that had conducted a systematic survey of the county’s hedgerows and Dr Janice Fuller, who had carried out the survey, and council staff Marie Mannion (Heritage Officer) and Brídín Feeney (GIS Officer), provided us with the results so that we could easily select suitable sites for the hair tube study. At the end of the fortnight, the tubes that still had the chicken in place needed to be carefully – and quickly – put into strong plastic bags for disposal. Not an attractive job!
The Mostela
In 2017, the Dutch Small Mustelid Foundation introduced an innovative new tool for monitoring small mustelids — the Mostela, which is a wooden box with a trail camera inside pointing at an open-ended plastic tube that runs through it. One side of the plastic tube is removed, so any movement by an animal entering the tube would trigger the trail camera. The design takes advantage of the natural behaviour of stoats, which often investigate small tunnels while hunting prey such as rabbits and rats (Mos & Hofmeester, 2020).
Building on this idea, VWT worked with Brian Hughes, a master's student from Queen’s University Belfast, in 2019 to trial a modified version for the Irish stoat. The study compared the effectiveness of two camera setups — one placed inside the Mostela, and a second positioned externally as a standalone trail camera. The study ran for 13 weeks from April to July at 12 sites in Counties Mayo and Galway.
Interestingly, stoats were recorded more frequently inside the Mostelas, though external cameras detected them at more sites overall (Croose et al., 2021).
The study was repeated in 2021 using a slightly larger tunnel design, as part of VWT’s ongoing efforts to refine and improve non-invasive stoat detection methods.
Although the Mostela studies successfully detected Irish stoats, this method is also not feasible at a landscape scale.
Present
Irish Stoat Citizen Science Survey 2023-2025
This survey has been our most ambitious stoat project, and was a large-scale, collaborative effort powered by the public to learn more about one of Ireland’s most elusive mammals.
The survey ran from February 2023 to February 2025 and was delivered in partnership with the National Biodiversity Data Centre, the Centre for Environmental Data and Recording (CEDaR), and the University of Galway. By inviting members of the public to report stoat sightings, data were collected throughout the island of Ireland over a full two-year period.
Thanks to the enthusiasm of citizen scientists, 1,080 records were submitted. After careful validation, 816 of these were confirmed as Irish stoat records. This is an impressive figure that is almost five times higher than the number recorded in the two-year period (2021–2023) before the start of the Irish Stoat Citizen Science Survey.
Making sense of the data
Citizen science surveys based on sightings, such as this one, can be a valuable method for gathering data over extended periods of time and across a wide geographical area. Additionally, such surveys engage the public, promote education and raise conservation awareness. However, there are limitations to consider when interpreting the data generated by such surveys. Since citizen science data collection often happens near human settlements or accessible areas (roads, parks), this needs to be considered as a potential source of bias.
To address these issues, a range of statistical models were applied to the results to explore how the stoat sightings correlated with factors such as human population density, settlement patterns and road networks.
Habitat suitability and ecological niche models were also run using the verified stoat presence data. These models helped assess whether apparent gaps in the data were due to a genuine absence of stoats or the result of differences in surveyor effort or availability in certain areas.
What did the models show?
The models tested offer us a picture of stoat habitat suitability across Ireland. This approach allows us to better understand not just where stoats are found, but also where they might be present but have gone undetected due to survey limitations. The use of citizen science, paired with robust ecological modelling, is helping us fill in key knowledge gaps about the Irish stoat.
The Road Ahead
As with any modelling exercise, predictions are only the beginning; they need to be tested and refined in the field. Looking ahead, the next phase of our work will focus on validating our habitat suitability model by revisiting areas which the model suggests have suitable habitats but few or no stoat records were reported.
Follow-up studies will focus on a subset of survey sites, using a combination of hair tubes, Mostelas and trail cameras, using a variety of lures to help improve detection rates.
Sharing knowledge across the Irish Sea
In May 2025, the VWT Ireland Team travelled to the Isle of Man to take part in Manx Wildlife Week with a talk ‘The Manx Stoat – it’s all in the tail!’. We presented insights into our shared subspecies of stoat and the survey methods we tested in Ireland that could be adapted for use on the Isle of Man. The talk can be watched here: youtu.be/NgZ6YWoG3Y4
Our visit also included a productive meeting with Manx Wildlife Trust to discuss launching a Manx Stoat Citizen Science Survey in 2026. By expanding this collaborative approach across the full range of the Irish stoat, we can build a more complete picture of its distribution, behaviour and habitat needs — and support its conservation on both sides of the Irish Sea.
A HUGE thank you to our volunteers
Our work on the Irish stoat would not have been possible without the dedication, time and enthusiasm of hundreds of volunteers across Ireland. Their willingness to report sightings, place and check equipment, and watch hours of trail camera footage has been instrumental in shedding light on one of Ireland's most elusive mammals. To all our volunteers, THANK YOU!
Want to help?
Your sightings are still invaluable to the ongoing research into the status of the Irish stoat.
- If you see a stoat on the island of Ireland, submit your sighting via the National Biodiversity Data Centre.
- If you see a stoat on the Isle of Man, report your sighting to Manx Wildlife Trust by emailing enquiries@mwt.im
By participating in Citizen Science, you will help fill critical knowledge gaps and contribute to any future actions for the Irish stoat.
A HUGE thank you also to our funders and supporters
This survey was possible due to initial funding from the Irish Environmental Network and National Parks and Wildlife Service in 2022 that enabled us to plan the survey and launch it in February 2023.
We are grateful to National Parks and Wildlife Service for additional funding received in 2024 that enabled us to conduct our analysis of the data collected during the survey. We are also grateful to The Heritage Council for core funding received in 2024 that supported the recruitment of a Species Conservation Officer who undertook the validation of records received from the National Biodiversity Data Centre. Also grateful thanks to Colin Lawton for his advice during the planning stages of the survey and for designing the stoat logo.
Huge thanks to Oisín Duffy at the National Biodiversity Data Centre for setting up the survey webpage and collating results.
Further reading