Flooding at any season stimulates the breeding of ibises, and the white ibis, Threskiornis molucca (Cuvier), responds earlier than the straw-necked ibis, T. spinicollis (Jameson). Band recoveries show that both species disperse widely throughout Australia from breeding centres in the south. Measures are proposed for management of the Macquarie Marshes, New South Wales, as a waterfowl reserve in which the limited volume of controlled water would be utilized economically to ensure that breeding of ibises coincides with the spring emergence of the Australian plague locust, Chortoicetes terminiferaWalker.