Abstract Red foxes (Vulpes vulpes) are one of the most widely distributed carnivores globally and are well known to scavenge in their native range. Less is known about the factors influencing Red Fox scavenging in areas where they have been introduced, which limits our ability to make predictions about the role of carrion in supporting their populations. Here, we explore scavenging data from 119 kangaroo carcasses monitored across 3 separate bioregions in Australia (alpine, temperate, and arid) where red foxes have become well-established since their introduction. Carcasses were monitored for 30 d in different seasons (warm and cool) and habitats (open and closed canopy) in each bioregion using camera traps. We characterized Red Fox scavenging activity (i.e., time to first detection, duration of time spent scavenging, and patterns in scavenging activity within the diel cycle) under different environmental scenarios, including in relation to the presence of the Dingo (Canis dingo), a larger competitor. Red foxes visited 65 (55%) of the monitored carcasses, resulting in 781 independent visitation events. Most visitation events occurred in the cool season (81%), and the arid bioregion (62%). Red foxes spent 1.81-fold more time scavenging in the arid bioregion than the alpine bioregion, with no difference in time spent scavenging between the alpine and temperate bioregions. Red foxes were also detected at carcasses 2.28-times faster in the arid compared to the alpine bioregion, with times to Red Fox detection similar at carcasses in the alpine and temperate bioregions. In contrast, time to detection at carcasses by dingoes were 0.41-times slower in the arid than the alpine bioregion, but 4.87-times faster in the temperate than the alpine bioregion. Red foxes also exhibited differences in their daily peak activity at carcasses across habitats in the temperate and arid bioregions and also in response to the presence of dingoes, with daily peaks in Red Fox scavenging activity before and after daily peak Dingo activity in the arid and temperate bioregions, but to a lesser extent in the alpine bioregion. These results suggest that red foxes make extensive use of carcasses in Australia, especially in cool seasons and in less productive arid bioregions. The results also suggest that red foxes avoid dingoes, indicated by differences in temporal patterns of carcass resource use. These results are useful for determining when and where carcasses may be supporting invasive Red Fox populations in Australia, and more broadly, enhance our understanding of how red foxes may opportunistically exploit carrion worldwide.
Newsome et al. (Mon,) studied this question.