Blog written by Holly English and Anthony Caravaggi. Read the full paper here. Photo of captive red-necked wallaby by Claire Bushell.
The answer to that question may surprise you. The red-necked wallaby (Notamacropus rufogriseus) may be synonymous with Australia, but it also shows up in some more surprising places. Popular in zoos and proving themselves to be effective escape artists, wallabies exist as alien species in several countries. They have caused notorious damage in New Zealand, but in Europe they have largely flown under the radar.
Red-necked wallabies were first brought to Britain for display in zoos and private collections in the early twentieth century. Many escaped or were deliberately released, particularly during World War II when fence maintenance and exotic animal care were low priorities. This resulted in small populations of feral wallabies living in Britain. The most renowned population of wallabies was found in the Peak District and was subject to study by Derek Yalden for many years. The last of the Peak District wallabies is thought to have died in 2009 with occasional sightings since then thought to be connected to deliberate releases by local wallaby enthusiasts. Since then, free-roaming wallabies in Britain have been somewhat forgotten, though sometimes cause a stir in local and national media reports when spotted bounding across a road or showing up in someone’s garden. Understanding the presence, distribution and establishment potential of non-native species is important to wider biodiversity management and so we explored the current status of wallabies in Britain to investigate whether they had largely died out as assumed or were surviving at low population levels.
To determine the current status of wallabies, we used a combined approach. We contacted every Local Environmental Record Centre (LERC) and the National Biodiversity Network requesting any records of wallabies reported between 2008 and 2018. We also searched through media articles and set up a bespoke website and Facebook page where members of the public could report wallaby sightings, as well as tweeting about the initiative from our personal profiles. Out of all these methods, media articles provided the most records for our search.
We compared our collated data set to the wallaby records reported in Yalden (2013). Our data set contained more wallaby records, with a wider and more southerly distribution. However, Yalden’s records included both populations and individual sightings, whereas almost all our records were of individuals. Two media articles reported joeys but whether wallabies are breeding in the wild is inconclusive. These cases could be escaped females with joeys in the pouch rather than a full breeding cycle in the wild. Where possible, we noted the calendar month as well as the year of individual wallaby sightings. Of these records, a quarter took place in August. The reasons for this are uncertain. Maybe feral wallabies in Britain are more active and moving more widely at this time of year or maybe their potential observers are!
As is often the case in research, this study poses more questions than it answers and points towards meaningful avenues for future research. Are wallabies breeding in the wild or simply great escape artists? How might wallabies impact other species through competition or disease? We hope that our work provides a starting point and map to key areas for people pursuing these questions. Sensible approaches might use e-DNA or scat surveys to determine the presence of a population as opposed to roaming escapees. Key areas for such future wallaby investigations include the Chilterns and Cornwall.
While the story of Britain’s wallabies is curious in and of itself, the implications here go beyond the ecology of a single species. Unexpected wildlife sightings are exciting to the public, but people are more likely to call a local newspaper or post about it on social media than to contact their local or national biological record centre. If media reports about unusual wildlife being spotted included information about record centres, or indeed forwarded relevant photographs and reports to record centres directly, this could serve as an important avenue for rare species records. More information about biodiversity recording in the UK can be found at https://nbn.org.uk/ and http://www.alerc.org.uk/ for local and national initiatives, respectively. Residents of Northern Ireland can also refer to https://www.biodiversityireland.ie/ (which uses an all-island approach to collating biodiversity data from the Republic of Ireland and Northern Ireland). Who knows? Maybe sharing information about biological record centres in connection to such rare and unusual species sightings can even encourage more members of the public to get outdoors enjoying nature and documenting all the creatures around us.
Yalden, D. (2013) The end of feral wallabies in the Peak District. British Wildlife, 24.