Beware the sly fox. For the first time, red foxes in Australia have been documented climbing trees to look for baby koalas and other unsuspecting creatures to munch on.
The European red fox (Vulpes vulpes) was introduced to Australia in the mid-1800s for recreational hunting. It quickly developed a taste for ground-dwelling native species like bilbies, wallabies and numbats, leading to savage declines in their numbers.
Until now, tree-dwelling animals have been considered safe. But recent work led by Valentina Mella at the University of Sydney, Australia, suggests this might not be the case.
In mid-2016, Mella was studying koalas on a property in the Liverpool Plains, about 250 kilometres north-west of Sydney. As part of her research, she set up cameras to record the animals visiting drinking fountains in eucalyptus trees spaced several kilometres apart.
When she watched the footage, she was astonished to find multiple instances of red foxes scaling the trees. “I was quite shocked because I’m from Europe and I’ve never seen a fox in a tree before,” she says.
The owner of the property told Mella that he regularly sees red foxes in trees, sometimes as high as 4 metres off the ground.
Although the footage did not capture any instances of active predation, the foxes could be seen sniffing around and following the scent of other animals that had been in the trees. This was good evidence they were on the hunt, says Mella.
They did not touch the drinking fountains, suggesting they were not there because they were thirsty.
Euan Ritchie at Deakin University in Victoria, Australia, says he has heard anecdotal evidence from other ecologists of red foxes climbing trees. It may be more common than we think, he says. “Red foxes are quite agile animals, so it makes sense,” he says.
Foxes are most likely targeting tree-dwelling species because they are easier to sneak up on than ground-based animals that have become accustomed to them, says Mella.
“It’s probably hard to catch rabbits, for example, because they are used to foxes and are programmed to escape,” she says. “But if a little feathertail glider or baby koala is just sitting there, that’s easy prey.”
Moreover, it is easier for foxes to climb trees in Australia than in Europe because eucalypts have lots of bumps that provide good footholds, says Mella. “They’re not like pine trees in Europe, which have very small branches,” she says. There are very few records of red foxes scaling trees in their native habitat, she says.
If future research confirms that red foxes are preying on tree-dwelling species, it will be a devastating blow, says Mella. “Foxes are curious, agile and opportunistic,” she says. “It’s a terrible combination for native Australian animals.”
Journal reference: Australian Mammalogy, DOI: 10.1071/AM16049
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