The breeding population of Ospreys (Pandion haliaetus) in South Australia was estimated at ~52 pairs in 2005. These were sparsely distributed (one pair/30.1 km of coastline) from the eastern Bunda Cliffs in the west of the state, to Kangaroo Island in the east, with most of the population on western and southern Eyre Peninsula in the Great Australian Bight region. Most nests were constructed on broken sections of coastal cliff and near-shore rock-stacks, with a small number on man-made structures and one active nest in a tree. The population is geographically isolated, with the westernmost territory in South Australia ~1000 km from the nearest known breeding sites to the west, in Western Australia, the nearest population to the east is in north-eastern New South Wales, >1500 km distant. There is evidence for an overall population decline in South Australia as only historical breeding records were found for upper Spencer Gulf and for the Murray River indicating a substantial reduction in range. In addition, some nesting sites on Eyre Peninsula and Kangaroo Island are considered vulnerable to disturbance from unmanaged coastal recreation and the encroachment of residential and tourism development.