Movement ecology and diet are consistent across sexes in the endangered Southern Black-throated Finch (Poephila cincta cincta)

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.