Food calling and audience effects in male chickens, Gallus gallus: their relationships to food availability, courtship and social facilitation
1994
Evans, C.S. | Marler, P.
Male chickens produce characteristic pulsatile calls upon discovering food and are more likely to call in the presence of a hen. Calling thus appears to be dependent upon food and to be modulated by social context. An alternative explanation is that food calls are in fact components of a complex courtship display. The relationships between food calling, food availability and courtship were examined in a laboratory setting. Subjects interacted with an unfamiliar hen and were then given access to food, using an instrumental conditioning procedure. In some control conditions, the males were tested alone, while in others food was unavailable. Food calling, sexual display and the rate at which males performed an operant response were measured. Call production increased dramatically when food first became available, both when a hen was present and when males were alone. This change in call rate did not occur during control trials without food. Sexual display was maximal when males were first placed in the test chamber with a hen present and declined exponentially thereafter. The presence of a hen had no effect on food calling during this period. Food calling was thus principally elicited by food stimuli and was not reliably associated with courtship behaviour. When a hen was present, males called at a higher rate following food presentations. In contrast the rate at which males worked to obtain food was unaffected by social context. The 'audience' effect therefore acts specifically to potentiate calling and is distinct from social facilitation.
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