Little Eagle (Hieraaetus morphnoides) nesting sites are reliable bioindicators of woodland bird richness on the New England Tablelands, New South Wales, Australia

Abstract

Anthropogenic activity that causes habitat fragmentation and degradation is threatening biodiversity globally. Some species are highly sensitive to habitat disturbance, making them reliable indicators of changing ecosystem status, supporting biodiversity management and monitoring activities. While top predators such as raptors are typically viewed as potential indicator species of intact woodland due to their habitat requirements and trophic level, this relationship should be directly tested. We examined whether the presence of Little Eagle ( Hieraaetus morphnoides ) nest sites in woodland patches on the New England Tablelands in northeast New South Wales, Australia were potential indicators of higher woodland bird richness. We compared 30 sites with active Little Eagle nests to a nearby site (within ~ 3 km) of similar habitat and size where eagles were not nesting. At each site, we conducted 20-min standard 2 ha bird survey protocols, completing two surveys over two survey periods in early and late austral spring. Bird species associated with degraded woodland were generally uncommon at both eagle nest and control sites suggesting that both were of relatively high woodland quality. Nonetheless, we found that Little Eagle nest sites had significantly higher species richness overall, including higher numbers of threatened species of conservation concern, and a greater proportion of woodland bird species typically associated with high quality, intact woodland habitat. Together, our results demonstrate that the presence of Little Eagle nests are a reliable bioindicator of higher woodland bird richness and by extension woodland quality in the region.

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