Foraging Behavior of Pardalotes in South-eastern Australia: Comparison of the Taxa Pardalotus punctatus, P. xanthopygus and P. striatus 'striatus', 'ornatus' and 'substriatus'

Abstract

Two superspecies of pardalotes (Pardalotus striatus and P. punctatus) co-exist throughout south-eastem Australia with extremely high overlap in foraging behaviour. With data from seventeen sites, I examine this foraging behaviour and coexistence between these two superspecies and between taxa within the two superspecies. Foraging behaviours of three taxa within the P. striatus complex were virtually indistinguishable. The foraging of P. punctatus was very similar to that of P. xanthopygus, and there were no significant differences between the sexes of these spotted pardalotes. Spotted pardalotes foraged more at the periphery of foliage than did striated pardalotes, perched less often on twigs and branches but hovered more. This is related to the smaller size of spotted pardalotes. All taxa changed their foraging significantly between different study sites, and the direction of these changes were similar for all taxa. Local overlaps in foraging behaviour between the two superspecies were unrelated to local levels of prey abundance. There were some seasonal foraging changes that were consistent for all taxa. In winter, feeding rates increased and foliage extremities were used less often. Both spotted (particularly) and striated pardalotes changed foraging behaviours when in different tree species. These changes were correlated with differences in leaf size, leaf shape, tree height and densities of invertebrates and psyllids. Spotted and striated pardalotes were more segregated in tree species use than in type of foraging action.