Den selection in woodland populations of northern quolls (Dasyurus hallucatus)

Northern quolls (Dasyurus hallucatus) are the largest marsupial predator in northern Australian savannas. Once abundant, they have declined sharply over the past 50 years and are now considered locally extinct over much of their former range. Local extinctions have been most pronounced in eucalypt woodlands, with rocky outcrops acting as refugia. To prevent further decline of this species, we need to understand what factors allow remaining woodland populations to persist. Of the regions where northern quolls persist, Cape York Peninsula has the least studied populations of northern quolls. Only three remnant populations have been identified across western Cape York Peninsula, all inhabiting eucalypt woodlands. I fitted tracking collars to 10 individual quolls in March 2019. The collars were equipped with very high frequency radio transmitters and GPS loggers, allowing me to track the quolls to their day-time den sites over a 4-week period. I identified 57 den sites, comprising 37 hollows in standing trees and 20 in fallen logs. Of the 57 den sites, 13 sites were used repeatedly over the survey period, suggesting individual quolls preferred characteristics of these den sites over others. I found 70% of den trees were Eucalyptus tetrodonta and 60% of den trees were categorised as having a distinctive leaning growth form that promoted the likelihood of hollow development. Quolls also showed a preference for long, fallen logs as ground dens. My results highlight the importance of large, hollow-bearing trees as a critical resource for northern quolls in eucalypt woodlands.