Effects of rainfall in the arid zone on waterbird abundance at a wastewater treatment plant in coastal South Australia

We investigated which species of waterbirds at Bolivar, a wastewater treatment plant in Metropolitan Adelaide, South Australia, are likely to have been immigrants from the ephemeral wetlands arid zone. To do this, we compared abundance waterbird observed Bolivar during dry period eastern zone late 2018 and 2019 with that subsequent wet 2020–2022. Pink-eared Duck Malacorhynchus membranaceus, Grey Teal Anas gracilis, Australasian Shoveler Spatula rhynchotis, Hardhead Aythya australis Blue-billed Oxyura were all more abundant arid-zone period. By contrast, Australian Shelduck Tadorna tadornoides, Eurasian Coot Fulica atra Black Swan Cygnus atratus showed increased spring early summer years, no marked differences between periods Wader breed Northern Hemisphere – Sharp-tailed Sandpiper Calidris acuminata Red-necked Stint C. ruficollis also tended be year, as did Avocet Recurvirostra novaehollandiae, whereas Pied Stilt Himantopus leucocephalus breeding by this taking place spring. These data suggest is critically important conservation site for various use location refuge times Australia.