Targeted sampling successfully detects the cryptic and declining arboreal marsupial (Phascogale pirata) in northern Australia

The threatened northern brush-tailed phascogale (Phascogale pirata) is one of the most poorly known mammals in Australia. While the few available records indicate a decline in its distribution and abundance, it has not previously been subject to intensive targeted survey. Here, we trialled a specifically tailored methodology for detection of P. pirata, with the aim of informing ongoing survey and monitoring of this species. We deployed 50 motion-sensor cameras (spaced closely together in a grid 500 × 1000 m) on Melville Island (Northern Territory, Australia), between June 2018 and May 2019. Cameras were baited and secured to trees ∼3 m above the ground on a bracket facing the trunk. We selected for large (>30 cm diameter at breast height [DBH]) trunks of the dominant tree species (Eucalyptus miniata, E. tetrodonta and Corymbia nesophila). We detected P. pirata 16 times on eight cameras over the duration of the study, finding that detection was most likely on large (DBH >41.5 cm) E. tetrodonta trees during the wet season. Our results indicate that survey effort for this species should be seasonally targeted and focussed on large trees. However, the efficacy of additional methods (nest boxes, Elliott traps) and a comparison between detections on arboreal versus ground-based cameras requires further investigation. We highlight the importance of conducting additional work on this species, as little is known about its ecology, population trends and threats, making it difficult to assess its conservation status. Without more targeted work, P. pirata is at risk of slipping into extinction unnoticed.