Monitoring nocturnal birds in remote landscapes poses challenges for conservation. The Northern Masked Owl (Tyto novaehollandiae kimberli), a threatened raptor of northern Australia, illustrates these difficulties by having a distribution and conservation status that remains poorly resolved. Passive acoustic monitoring offers a scalable, non-invasive alternative to traditional survey methods, but its effectiveness depends on understanding species-specific vocal behaviour. We deployed autonomous recording units at four roost sites (three also nest sites) used by adult pairs, in riparian habitats of the Kimberley (Western Australia) and Wet Tropics (Queensland). A custom call recogniser was developed, and precision-recall curves were evaluated to identify a score threshold that maximised detections while minimising false positives. Using this threshold, we detected 10,227 Northern Masked Owl adult screech calls from 987 recording nights. We analysed diel and monthly patterns in vocal activity and assessed how detectability varied across time, site and breeding status. Vocal activity peaked after dusk and before dawn, and seven nights of sampling were sufficient to achieve >= 95% detection probability for any month. Adult calling rates declined during periods when dependent young were present, indicating reduced detectability during this period. Our results demonstrate that passive acoustic monitoring is an effective method for detecting Northern Masked Owls around known roosts and nests when targeted within core-use habitat. We recommend that future surveys prioritise structurally suitable habitat, align recording schedules with crepuscular calling peaks, incorporate a minimum of seven nights of sampling and include juvenile begging calls in post-survey analyses during breeding periods.
Understanding sex-related differences in ecology is essential for effective conservation strategies, especially in species that exhibit subtle to no sexual dimorphism. This study examines the Desert Uplands population of the Southern Black-throated Finch (Poephila cincta cincta); an endangered species endemic to north-eastern Australia, focusing on key ecological aspects, including sex ratio, movement ecology, and diet. Although previously considered sexually monomorphic, we found subtle sexual dimorphism in throat patch size (17.1% larger in males) and wing length (7.48% larger in males), with no significant differences in other morphological traits. We found a balanced adult sex ratio (52.3% females, 47.7% males), indicating no significant sex bias; a key indicator for ensuring mating opportunities and breeding success. Despite these differences, only 67.6% of individuals could be sexed accurately based on these traits. We also examined the movement ecology of the species and found no significant sex-based differences in home range size or movement distance, consistent with the subspecies' tendency to live in mixed-sex flocks. Diet analysis, based on DNA metabarcoding of crop and faecal samples, indicated no significant sex-based dietary divergence, with both sexes consuming a similar variety of grass seeds. These findings highlight the importance of understanding the ecological dynamics of the Southern Black-throated Finch for conservation efforts, suggesting that further studies on juvenile dispersal, and advanced morphometric techniques may improve understanding of this species.
Bird assemblages were surveyed on two adjoining conservation reserves in north-western NSW over six years through a sequence of dry - wet - dry conditions that included Australia's driest and warmest year on record. Surveys aimed to identify bird-habitat associations and assess changing abundances. Species richness was highest in 'wet' years, but in contrast to all previous studies, total bird abundance was highest in the two driest years driven by the superabundance of two Eyrean nomadics, Masked Woodswallow (Artamus personatus) and White-browed Woodswallow (Artamus superciliosus), coinciding with Yapunyah (Eucalyptus ochrophloia) flowering events. Seven broad patterns of species abundance were found. Less than half (42.5%) of the bird species were consistently present. Inter-annual differences in the composition of bird assemblages were mostly due to nomadic species. Diet was a reasonable predictor of movement behaviour but foraging guilds did not map directly onto movement groups. Each foraging guild had species with different movement behaviours and vice versa. Patterns of species' abundances did not always conform to their expected movement behaviour. Both vegetation and rainfall had a role in structuring bird assemblages. Variation in bird assemblages was significantly correlated with remotely sensed Normalized Difference Vegetation Index (NDVI).
