To Drain or Not to Drain?—Intermittent Swamp Drainage and Waterbird Breeding

SummaryCrome, F.H.J. (1988). To drain or not to drain?—Intermittent swamp drainage and waterbird breeding. Emu 88, 243–248.The breeding activity of waterbirds—ducks, cormorants, ibises, herons and grebes—are examined in relation to water level fluctuations at Booligal, N.S.W. In the swamp complex studied, most species bred best after a flood on a previously dried out basin. A rise in water level in an already wet basin had no effect. However, the specialist fishers—Darters, Little Black Cormorants and Intermediate Egrets—bred best when the swamps had been filled for some time and a climax of Ribbonweed and fish had developed. The importance of a previous drying phase to waterbird breeding rather than a flood is stressed and the usefulness of drying swamps intermittently in waterbird management considered.