Alarm call responsivity of mallard ducklings: VIII. Interaction between developmental history and behavioral context

Mallard ducklings (Anas platyrhynchos) inhibit their vocal behavior upon hearing the maternal alarm call of their species. The present study assesses the interaction of the ducklings' experiential history with the environment in which they are tested. If ducklings are reared and tested to the alarm call in small social groups, they respond by dramatically inhibiting their vocalizations. If, however, socially reared ducklings are tested to the alarm call individually in an open field, responsiveness drops precipitously. In addition, individually reared ducklings respond at a far greater level to the alarm call when tested individually, not in groups. Thus, there is an interaction between the rearing history and the testing environment such that the same rearing history leads to different behavioral outcomes depending on the context in which the ducklings are observed. This demonstrates the importance of behavioral context, in addition to developmental history, as one of the determinants of behavior.