The Juvenile Food-begging Calls, Food-swallowing Vocalisation and Begging Postures in Australian Cockatoos

Abstract

The juvenile food-begging calls, food-swallowing vocalisation and begging postures of cockatoos were studied and compared with those of other Australian parrots. The begging call of most cockatoos is a repetitive harsh-sounding wheeze, differing in tone from the hissing begging note of lorikeets, and quite different in tone, structure and tempo from the whistling begging notes of most other Australian parrots (descriptions of which will be presented in three subsequent papers). The food-swallowing vocalisation seems to be unique to the cockatoos. Only two species of cockatoo, thought to be the most 'primitive' (Cockatiel Nymphicus hollandicus and Gang-gang Callocephalonfimbriatum), have the same begging posture as most other parrots. The occurrence of a basically similar 'straight' wheezing begging note, and possession of a food-swallowing vocalisation, in all five genera of the cockatoos reflect a degree of uniformity in this natural group that is surprising in view of its apparently ancient lineage.