Foxes in trees: a threat for Australian arboreal fauna?
Mella, VSA, McArthur, C, Frend, R & Crowther, M 2018, Australian Mammalogy, vol. 40, no. 1, pp. 103-105.
For the first time in Australia, researchers have observed red foxes (Vulpes vulpes) climbing trees. It is not yet known whether such behaviour is common or if red foxes can prey upon arboreal species; however, this surprising behaviour may have negative consequences for koalas.
As part of a separate study, researchers placed artificial water stations in koala habitat trees at a private property near Gunnedah in north-west New South Wales and monitored their use with camera traps. On three separate occasions from April to July 2016, red foxes were recorded climbing these trees. The recording of the first incident commenced with a fox already positioned in the fork of a poplar box (Eucalyptus populnea), 1.36 m above the ground. Having no-low lying branches to facilitate climbing, its rough bark may have enabled the fox to ascend the tree. Remaining in the tree for one minute, the fox investigated and appeared to follow the scent of a koala recorded climbing the tree five days earlier. The second incident occurred in another poplar box. After circling the base of the tree, the fox leapt to a height of 1.3 m where it anchored its front legs in the fork of the tree and gripped the trunk with its hind legs. The fox then investigated the branches for around 20 s before descending. This tree had also been recently visited by sugar gliders, koalas and birds. In the final incident, a fox beneath a poplar box surveyed its branches before ascending the tree in the same fashion as in the previous video. A koala had climbed the tree only minutes earlier. Despite the foxes appearing to trail koalas in some instances, no interactions or predatory behaviour was recorded.
Red foxes have only once previously been recorded in the literature to climb trees, and this report is the first to document the behaviour in Australia. In the previous report, red foxes in Canada were suggested to climb trees as a desperate act to search for prey during periods of food scarcity. In this instance, however, food scarcity was unlikely to be a factor as several prey species such as hares and mice were abundant at the study site. It is possible that the red foxes observed here were attracted to the scents of potential prey species in the trees, especially as the artificial water stations had been utilised by a variety of wildlife.
Introduced predators are one of the most significant threats to Australian animals, and particularly mammals. Although no predation on koalas was observed in this instance, the findings shared here present red foxes as a potential threat to arboreal mammals. Even without the threat of direct predation, sublethal effects such as behaviour alteration can also place additional stresses on koala populations. It will be, therefore, important to continue to monitor this potential threat.
Summarised by Joanna Horsfall
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