Waterbirds and other birds of the Arcoona Lakes, arid South Australia, 2022–2023

The waterbirds of the Arcoona Lakes in central northern parts of South Australia have previously been studied following large rainfall events in 1989 and 2007. These ephemeral wetlands refilled in 2022, providing an opportunity to study the lakes for a third time. Unlike the previous rainfall events, where much of south-eastern Australia was relatively dry, there was extensive and widespread rainfall across Australia throughout 2022. Despite the widespread availability of habitat, waterbirds still flocked to the Arcoona Lakes. We recorded 48 species, with total abundance comparable to the 2007 rainfall event, but lower than the 1989 event. Single-day abundance at Coorlay Lagoon exceeded 20,000 individuals, highlighting these wetlands as Nationally Important (international Ramsar Criterion 5, adopted by BirdLife Australia for identifying nationally important bird sites). Across all three studies, 64 species of waterbird have been recorded using the Arcoona Lakes, including migrants from the Northern Hemisphere, as well as large congregations of Blue-billed Duck Oxyura australis and Freckled Duck Stictonetta naevosa. In total, 25 species have been recorded breeding at the lakes. Inland wetlands remain relatively understudied; our surveys provide important data on the use of inland wetlands by waterbirds, and continue the longitudinal research at the Arcoona Lakes that now spans more than three decades. Since the Arcoona Lakes are seldom visited, we also include records, and some photographs, of bird species other than waterbirds.