The ecology of wild ducks in inland New South Wales. IV. Breeding

Abstract

The breeding of the black duck, Anas superciliosa Gmelin, the grey teal, A. gibberifrons Muller, and the pink-eared duck, lialacorhynchus membranaceus (Latham) has been studied. The breeding of the grey teal is timed to coincide with increasing water level, and that of the pink-eared duck with declining water level following flooding. Both species may breed at any time of the year when the appropriate water conditions occur. The emergence of ducklings in each species coincides with a great increase in the animal food available to them. That increase in animal food is initiated by the original alteration in water level. The black duck has a more regular breeding season than the other species, and some birds breed even though the season is adverse. Out-of-season breeding may occur, however, whenever exceptionally favourable conditions are present. It is concluded that, although environmental factors are of prime importance in regulating sexual activity in wild ducks, the influence of fixed annual factors (including long-term photoperiodism) on some species cannot be entirely ignored.