The behaviour of the pukeko,Porphyrio porphyrio melanotus

Abstract

Displays of the pukeko, Porphyrio porphyrio melanotus Temminck (Gruiformes: Rallidae) are described and analysed quantitatively. Aggressive displays centre around the beak, which is presented to the opponent in a position from which a peck can be given. Submissive or escape displays centre around the white undertail coverts, which appear to have evolved as a distinct submissive signal since they are in sharp contrast to the aggressive releaser, both in location and colour. Raising the wings serves to expose the undertail and to provide a contrasting frame. The development of the white undertail as a submissive signal may have paralleled the development of the large frontal shield, which serves to maximise the aggressive releaser. Most displays are ambivalent, signalling both aggression and escape. With increasing escape tendency the bill and frontal shield are so placed that pecking is decreasingly likely, and the wings are increasingly raised. In postures with high escape tendency the beak is placed on the ground or removed from the opponent's view, but only in pure escape postures are the white undertail coverts prominent. Displays which involve rapid removal of the beak and shield from the opponent's view are more common in close contact situations, such as hierarchical interactions between pukeko of the same group. A brief comparison is made with other published reports on gallinules.