Nest-sites and foraging of the White-bellied Sea-Eagle 'Haliaeetus leucogaster' on the subtropical eastern coast of Australia

Abstract

Nest-site characteristics (10 nests, of 9 pairs) and aerial foraging time-budgets of the White-bellied Sea-Eagle 'Haliaeetus leucogaster' were studied on the Gold Coast and Tweed Coast (Queensland/NSW border region) of subtropical eastern Australia. White-bellied Sea-Eagle nests were situated high (>10 m) on lateral branch-forks in tall (>18 m), living, large-boled trees (>1.1 m diameter at breast height), mainly eucalypts in open forest, within ~1 km of waterbodies, and between 220 m and 1.1 km (mean 460 m) from human settlements. From the coastal plain to the subcoastal foothills up to 8 km inland, nests occurred at elevations up to 75 m above sea-level, but most were at ≤5 m asl; nests were on flat land or on slopes, the latter commonly with a southerly aspect. Two focal pairs of Sea-Eagles each spent ~15% of observation time (20 h per pair) in foraging-related searching and commuting flight, and <1% of aerial foraging time in attacking prey. Hunting success averaged 45% in 20 observed attacks on prey. There was no significant difference between the two pairs in aerial foraging time-budgets and hunting success.