Key to the conservation of waterbirds on coastal floodplains in Australia is improved management of their wetland habitats. Waterbirds and wetlands of the Clarence River floodplain, in north-east New South Wales, were studied from 2005 to 2007 to gather ecological information about the waterbird species that use the floodplain and the physical properties of the constituent wetlands. The work contained in this PhD consisted of a review of historical accounts, including oral history, appraisals of the wetland types and waterbird species present, monitoring of selected wetlands for waterbirds and water quality, particularly salinity, and bathymetric mapping of selected wetlands. Also, the grazing habits of one species (Black Swan 'Cygnus atratus') were studied, and an assessment of the value of drains as waterbird habitat was undertaken. Finally, wetland management on the floodplain was reviewed to contextualise how this would most favour waterbirds.