Vocalizations of chicks and juveniles and the development of adult calls in the Aldabra White‐throated rail Dryolimnas cuvieri aldabranus (Aves: Rallidae)

Calls were recorded from eggs, chicks and juveniles of the Aldabra White‐throated rail Dryolimnas cuvieri aldabranus. A sonagraphic analysis was made of these calls, their behavioural contexts described and probable functions suggested. Three calls, the twitter, tiuu and contented peep were produced by chicks in the egg. All three calls may be derived from the basic peep first recorded some 36 hours before hatching. Shortly after hatching two more calls, the distress call and the alarm call, can be elicited from the rail chicks. Contented peeps and twitters are restricted to the repertoire of young rails. Song was first heard from wild rail chicks at the age of ten days and may develop from the contented peep. Three adult calls, the 'mp yeah, 'mptiuu and 'mpclick appear at the age of three months and six months later the adult vocal repertoire is completed by the appearance of 'mps, toks, purrs and nest‐defence squeals. With the exception of the 'mp, all adult calls can be derived from the vocalizations of chicks and juveniles.