Painting the Town Red: Investigating the Urban Ecology of Red Squirrels

September 2020 Student of the Month - Kat Fingland

PhD Research at Nottingham Trent University

Email: kathryn.fingland@ntu.ac.uk     Twitter: @FbyRedSquirrels  

From 21st to 27th September, it is Red Squirrel Awareness Week – celebrating those tufty-eared, nut nibbling charismatic creatures who are native to our British countryside.

Background

It has been predicted that approximately two-thirds of the global population will live in urban areas by 2050 (United Nations, 2019), dramatically altering the natural environment and presenting new challenges for our wildlife species. Consequently, there has been a growing interest in urban wildlife ecology in recent years. Historically urban areas have been ignored as potential wildlife habitat, but there is increasing evidence that they can be biodiverse with abundant resources. Although some species are negatively impacted by urban developments, others have the behavioural flexibility to adapt and even thrive in these new conditions.

One such urban-adaptable species is the red squirrel, which was historically widespread across the UK but has suffered from significant population declines following decades of habitat loss and the introduction of the grey squirrel (Sciurus carolinensis) from North America in the late 1800s. Grey squirrels are able to out-compete red squirrels for resources, resulting in competitive exclusion (Wauters et al., 2002), and they also carry a fatal infectious disease known as squirrelpox virus (Rushton et al., 2006). Subsequently red squirrels have been listed as Endangered in the new Red List for Britain’s Mammals (Mathews et al., 2018) and, following the relatively recent spread of grey squirrels to Italy, the continental population of red squirrels is also threatened (Bertolino et al., 2008).

I am in the final year of my part-time PhD at Nottingham Trent University researching how the red squirrel has adapted to live alongside us in urban environments. I am particularly interested in the potential suitability of towns and cities to act as refugia for the red squirrel, in order to contribute to their long-term conservation.

Data Collection

I’ve spent the past three summers in the town of Formby, Merseyside, which is one of the remaining red squirrel strongholds in England. Working closely with the Lancashire Wildlife Trust and their Red Squirrel Project Officer, we carried out live-capture trapping to record population demographics, insert PIT tags (for individual identification), and attach radio collars to a sub-sample of individuals. Trapping was conducted in the residential gardens of local volunteers, as well as in the National Trust-owned woodlands adjacent to the town. The radio-collared individuals were then regularly tracked and their locations recorded, which will be used for home range analysis.

Alongside the live-capture trapping and radio-tracking, I have been collecting a range of other data to incorporate into my analyses. These have included: monitoring the population mortality, such as the locations (e.g. hotspots) and causes (e.g. diseases, road traffic) of death; assessing genetic diversity of the population using samples collected from necropsies; determining habitat quality and quantity through seed crop surveys and ArcGIS mapping; and evaluating the availability and impact of supplemental feeding via a public survey. These additional data will be incorporated into the home range analysis, in order to investigate how these factors affect the red squirrels’ spatial patterns of habitat use.

Future Work

I am currently in the data analysis and writing up phase of my research, in the final year of my five-year contract. Preliminary findings have highlighted significant differences between the home ranges of the squirrels located in the urban area compared with the woodlands, as well as potential “hotspots” of mortality. As I progress with writing up my thesis, I aim to collate these findings to produce management recommendations for the study site and other red squirrel strongholds, in order to benefit long-term conservation efforts.

Through my research, the importance of urban greening and making space for nature in our anthropogenic environments has stood out to me. Although red squirrels have successfully adapted to live alongside us, they still need habitat corridors for dispersal and building dreys (i.e. nests), access to native seed-bearing trees (instead of ornamental species often found in gardens) for food, and protection from road traffic collisions. We need to manage our towns and cities sustainably, particularly as urban growth and intensification increases, so that we can continue to enjoy watching charismatic species, such as the red squirrel, in our gardens.

Acknowledgements

I would like to express my gratitude to the Lancashire Wildlife Trust, in particular the Red Squirrel Project team, for all of their expertise and help with my PhD over the past four years. I also want to thank the National Trust, all the volunteers, and the Masters’ students for their assistance with my fieldwork.

References

Bertolino S., Lurz P.W.W., Sanderson R., and Rushton S.P. (2008). Predicting the spread of the American grey squirrel (Sciurus carolinensis) in Europe: A call for a co-ordinated European approach. Biological Conservation, 141, 2564-2575.

Mathews F., Kubasiewicz L.M., Gurnell J., Harrower C.A., McDonald R.A., and Shore R.F. (2018). A Review of the Population and Conservation Status of British Mammals: Technical Summary. Natural England: Peterborough.

Rushton S.P., Lurz P.W.W., Gurnell J., Nettleton P., Bruemmer C., Shirley M.D.F., and Sainsbury A.W. (2006). Disease threats posed by alien species: the role of poxvirus in the decline of the native red squirrel in Britain. Epidemiology and Infection, 134, 521-533.

Wauters L.A., Gurnell J., Martinoli A., and Tosi G. (2002). Interspecific competition between native Eurasian red squirrels and alien grey squirrels: does resource partitioning occur? Behavioral Ecology and Sociobiology, 52, 332-341.

United Nations. (2019). World Urbanization Prospects: The 2018 Revision (ST/ESA/SER.A/420). Department of Economic and Social Affairs: New York.