Territoriality in a river specialist: the Blue Duck

Abstract

Territorial Blue Ducks Hymenolaimus malacorhynchos foraged on and defended territories more in the mornings and evenings than in the middle of the day. In contrast, intruding Blue Ducks foraged on territories more in the middle of the day. It is suggested that territorial birds are capitalising on a renewing invertebrate resource that varies in diurnal availability. Pair bond maintenance was also an important aspect of territoriality. Differences between territorial pairs suggest three factors in pair bond maintenance: first, pairs that are reproductively unsuccessful may seek new mates; second, separation caused by a synchronous moult may weaken pair bonds; and third, lone individuals can acquire territories and mates through a variety of means.