Wallabies from Australia have gained a foothold in the U.K. and may be there for good

Much ink has been spilled about the problem of invasive species from rabbits to cane toads in Australia, but a native Australian marsupial may have invaded right back by establishing a wild population in England.

Biologist Anthony Caravaggi spent several years collecting information on wallaby sightings in England over the last decade to get a sense of where and how many wild wallabies might be roaming the English countryside.

The red-necked wallaby is native to eastern Australia and the island state of Tasmania. It's a diminutive relative of the kangaroo, standing perhaps a metre tall, with a body about the size of a full-grown Labrador retriever.

Wallabies were first brought to England in the late 19th century for zoos and private collections.

"The oldest record we know of goes back to about 1890," Caravaggi, a lecturer in conservation biology at the University of South Wales told Quirks & Quarks host Bob McDonald. "During the World Wars, many were released into the countryside because priorities changed and facilities just didn't have the means to look after their animals and keep them alive. They're also adept escape artists. So they're still very popular in zoos and on small farms, and they escape quite regularly."

Wallabies have been hopping all over Britain

That might explain the 95 wallaby sightings between 2008 and 2018 — in gardens, lanes and along motorways — that Caravaggi was able to document and verify. These were from media reports and in responses to a website he established so people could report sightings directly to him. Sightings were relatively common in some areas, but so rare in others, they would often make headlines.

"The news reports are often accompanied by things like, 'I can't believe what I saw' or 'wondered what I was seeing,'" Caravaggi said. "We do have some areas where wallabies have attained a kind of celebrity status. So they have Facebook pages, web pages, and people in some areas are not accustomed to seeing wallabies."

Citizen-shot video of wild wallabies in Cornwall

There are no records as to how many animals have been imported from Australia for zoos and private collections that might have escaped, and so no clear count of just how many wild wallabies might be roaming the countryside in the U.K., according to Caravaggi. He speculates the number might be fewer than a hundred, or as large as several hundred. 

One of the earliest populations known was in the Peak District in northern England, near Sheffield. But those animals seemed to have disappeared by about 2009. Other documented groups are found on the Isle of Man as well as a small island in Loch Lomond in Scotland. But with the advent of social media, reported sightings in other places across Britain increased.

"The bulk of our sightings are actually down south with two particular hotspots being the Chiltern area, which is not far outside London and in Cornwall," said Caravaggi. "Cornwall turned out to be really interesting because we had two sightings of females with joeys in the pouch, which might suggest breeding."

"It's entirely possible they escaped with joeys in the pouch, we don't know. But the fact that they were two years apart does make me want to ask the question."

That question is, of course: Is the wallaby population increasing in England?

Caravaggi hopes his current study, in which he mapped the distribution of wallabies across the country, will be a step toward finding an answer in the future. He also hopes to understand if wallabies are having any negative impact on domestic plant or animal life. 

No worries about the English weather

Caravaggi is not surprised that wallabies have survived in Britain. There is an abundance of the same food resources the herbivorous marsupials are used to in Australia, like grasses, roots and weeds. The English climate is not a problem, either.

"The climate actually isn't that different. Eastern Australia and Tasmania can get hard winters," Caravaggi said. "The climate in Tasmania now is very similar to the current climate in the U.K. because of climate change, where winters are becoming milder as summers are becoming wetter. So in terms of adaptability compared to the native range, there's not that much difference."

That adaptability, together with the fact that they have enough to eat, safe places to live and are unlikely to be preyed upon, leads Caravaggi to believe that the wallaby will be in Britain for many years to come.

"I can't really see a good reason why if they are breeding, they couldn't become established in the long term and the fact that they're kind of a charismatic, fluffy mammal might make removing them a bit problematic."

Written and produced by Mark Crawley