Project Splatter – using citizen scientists to monitor wildlife roadkill

Amy Williams Schwartz, PhD researcher, Project Splatter

Sadly, the average commuter is familiar with the sight of a squashed badger on the side of the road. But, just how common a sight is this? In 2013, Project Splatter (www.projectsplatter.co.uk) was established to try and answer just that question. The main aim of the project is to address the fundamental questions of how many animals (specifically wildlife) are seen as roadkill, and to find out where and when this occurs. To achieve its aim Project Splatter collates wildlife roadkill reports from across the UK, using data submitted by members of the public, termed ‘citizen scientists’. Because data are submitted via social media so the project gained its name ‘Social media PLATform for Estimating Roadkill’, or ‘Splatter’. Since its inception in 2013 the project has grown exponentially with over 60,000 reports submitted to date.

Which species are most commonly seen as roadkill in the UK?: Over 200 species of vertebrates living wild or feral in the UK have been reported to the project since 2013, everything from hedgehogs to the more unusual wallaby. Almost without fail badgers are in the weekly ‘top 5’, and across all species badgers are currently the most reported roadkill animals (figure 1).

Figure 1. The 10 most commonly reported species observed as roadkill, and submitted to Project Splatter (by percentage of all roadkill records), 2013-2019.

Seasonality: The summer months are the peak times for roadkill observations, with most records occurring in the spring and late summer, with significantly fewer reports from the end of October through to the beginning of February (Figure 2). The highest number of records that the project has received in a single month occurred in April of 2017, with a total of 1768 records received, verified, and logged by the Project Splatter team! There are clear patterns in reporting rates of specific species throughout the year, with some having double peaks (bimodal) and others a single peak in roadkill. These patterns are likely to be linked to animal behaviour, with more reports (and therefore more roadkill) when species are more active during activities such as mating and foraging.

Figure 2. Percentage of roadkill records per month for all records reported to Project Splatter from 2014-2018 (years for which we have 12 months of data).

Where is the roadkill? Clear ‘hotspots’ exist across the UK. The top three counties in terms of numbers of reports are Hampshire, Sussex and Norfolk (Figure 3.). Once hotspots are identified we can use this information to inform mitigation measures, such as the most appropriate site for a wildlife crossing, or the placing of wildlife warning signs. Our data are currently being used to provide mitigation locations for a new government initiative to reduce wildlife roadkill and improve road safety for drivers.

Figure 3. Locations of roadkill reports to Project Splatter (black dots), with ‘hotspots’ (areas of high record densities), indicated by the warmer colours, using data submitted from 2013-2019.

No part of the UK is without roadkill, but the road type plays an important role in the amount of roadkill that is observed. The UK road types consist of motorways, ‘A’ roads, ‘B’ roads, and minor roads, and it would be reasonable to assume that motorways would be the deadliest for wildlife due to their large size, fast vehicle speeds and high traffic flow. It is, however, the A roads that are most dangerous for wildlife, with 52% of reported roadkill occurring along these roads and only 10% observed on motorways. This pattern may suggest that animals are actually avoiding motorways, perhaps because of disturbance due to traffic noise and artificial lighting.

Please get involved: Anyone can join in this roadkill research. Members of the public submit records by identifying the species seen, the date and location. Records can be submitted through our smartphone apps for Android and iOS phones, but we have a variety of other platforms through which records can be submitted, such as Twitter (@projectsplatter), Facebook, and an online survey form, via our website

We give our citizen scientists frequent updates through our social media pages in the form of figures and maps, and a weekly ‘splatter report’, published every Monday. This report summarises the sightings over the past week in terms of number of species, allowing us to see the changing rate of roadkill through the year.

Project Splatter is unique in the UK, being the only organisation to solely focus on recording incidences of all wildlife roadkill, year-round, and across the entire United Kingdom. We have already established partnerships with several NGOs such as local recording centres and wildlife groups, and share our data with the NBN Atlas. We would be interested to hear from any organisations that collect any UK wildlife roadkill data that would be interested in collaborating with us!