On the responses of laughing gull chicks (Larus atricilla) to the calls of adults I. Recognition of the voices of the parents

Twelve matched pairs of parent-raised and hand-raised laughing gull chicks from the same clutches were tested, at 6 to 8 days post-hatching, with successive presentations of playback of a recording of calls of their parents and recording of calls of parents from a neighbouring nest, in a situation in which they could approach or withdraw from the sound. The parent-raised chicks oriented towards the sound, moved towards the sound and called when the calls of their own parents were played; they tended to withdraw from the sound and sit silently when the calls of the neighbouring parents were played. The hand-raised chicks fled from the sound and crouched in silence in response to both calls of their parents and the calls of neighbours. They were more vocal and active in periods without sound than were the parent-raised chicks. It is concluded that laughing gull chicks in nature learn to recognize the individual characteristics of the calls of their parents, and to react positively to the calls, through interaction with their parents prior to the age of 6 days post-hatching.