Breeding habitat, nest-site characteristics and productivity of the little eagle (Hieraaetus morphnoides) near Armidale, New South Wales

Abstract

We aimed to elucidate nesting requirements and nest success of the threatened little eagle (Hieraaetus morphnoides). Nest sites (n=12 active and 2–5 recent historical nests) near Armidale, New South Wales, were measured in 2017 at three scales: the nest tree, the nest woodland (≤25m from the nest tree), and (using GIS) the landscape scale (within 200-m and 2-km radii of the nest). The eagles typically nested ≥14m above ground in the canopy of emergent (>20m tall) living eucalypts in sheltered positions (midslope, with a north-easterly to southerly aspect), in woodland patches >5ha (mean 76ha), <200m (mean 78m) from the woodland edge, though ≥11m (mean 190m) from an agricultural edge, ≥38m (mean 485m) from the nearest rural dwelling, >1km from suburbia, and farther from sealed roads (mean 832m) than gravel roads (mean 490m) than minor tracks (mean 291m). Breeding productivity in 2017–18 (n=15 and 18 territories, respectively) was 0.91 young fledged per attempt (clutch laid) and 0.67 young fledged per occupied territory per year. Nest sites were used annually for at least 3–7 years. Nest abandonments or site shifts were associated with human disturbance (e.g. clearing, earthmoving, subdivision and construction in or beside the nest patch), death of the nest tree or nest stand (‘eucalypt dieback’ or rural tree decline), pindone baiting for rabbits (Oryctolagus cuniculus), and displacement by wedge-tailed eagles (Aquila audax) and ravens (Corvus sp.). As most little eagle nests were located on private land, we recommend, inter alia, greater protection of breeding habitat, nest sites and foraging habitat, woodland regeneration (especially riparian), and a buffer around established nests of ≥1km from major developments such as urbanisation.

Breeding diets of the Little Eagle Hieraaetus morphnoides and Wedge-tailed Eagle Aquila audax in the Australian Capital Territory in 2011–2019

“…Rabbits were equally important in the diets of Brown Goshawks near Canberra during 2002-2010, and Goshawk numbers had not declined there Olsen 2019). Larkin et al (2020) did not investigate the relationship between Little Eagle breeding success and Rabbit abundance, but they found high fledgling productivity in 2018 during an increasingly dry period. It remains to be determined whether the severe 2018-2019 drought per se has had an effect on the Little Eagle's diet, breeding success and/or territory occupancy in the ACT, as other explanations are possible for changes in its demographics in that region.…”

“…urban expansion in Canberra, ACT), will assist in its conservation and management. For instance, significant gains have been made on understanding its breeding-habitat and nestsite requirements (Larkin et al 2020) and the homerange and roosting requirements of a fledgling (Olsen et al 2017).…”

Inheritance of plumage morphs in Little Eagles Hieraaetus morphnoides in northern New South Wales

“…Debus (2011) followed up with quantification of offspring morphs from parental morph combinations in the same area (Northern Tablelands of New South Wales), from field studies in 2006-2009. Here we combine and expand those data with findings from a larger sample of pairs and their offspring in the same area in 2017-2019 (Larkin et al 2020;CL & SJSD unpubl. data).…”

“…The area sampled was centred on Armidale (30°30′S, 151°40′E) on the Northern Tablelands of New South Wales, extending 60-80 km north-west to south, but mostly within a 20-km radius of the city. The study area is described by Debus & Ley (2009) and Larkin et al (2020), and a contextual map is provided by Debus (2008). Locally, Little Eagles inhabit remnant eucalypt open forest and woodland in undulating country at ~1000 m above sea level, and their foraging extends into more open habitats (scattered woodland and adjoining pasture).…”

“…The number of pairs and their morph combinations were tallied from studies of breeding pairs spanning three time periods: the 1980s (Debus 1989(Debus , 1991, 2000s (Debus 2011-2019(Larkin et al 2020SJSD & CL unpubl. data), not double-counting instances of the same sex/morph combination (e.g.…”