The cultural transmission of courtship patterns in cowbirds, Molothrus ater

In this study, I tested whether the courtship behaviours that facilitate patterns of assortative pairing and mating could be culturally transmitted across generations of brown-headed cowbirds. In an earlier study, I housed a first generation of young South Dakota cowbirds in one of two cultural backgrounds: (1) with adult social models from the;same population; or, (2) with adult social models from a behaviourally distinct Indiana population. During the breeding season, the first cultural generation of South Dakota cowbirds paired and mated assortatively based upon their cultural backgrounds. In the present study, I tested whether these courtship patterns could be culturally transmitted to a second generation of young South Dakota cowbirds. Serving as adult social models for birds of the second cultural generation were the first cultural generation of South Dakota birds from the previous study. During their first breeding season, the birds of the second cultural generation paired assortatively by cultural background at roughly a 3:1 ratio. In addition to the pairing data, the behavioural responses of females to the vocalizations of males indicated the influence of cultural backgrounds. This experimental demonstration of the cultural transmission of courtship patterns points to the importance of social environments as mechanisms whereby behavioural systems are inherited from one generation of animals to the next. (C) 1998 The Association for the Study of Animal Behaviour.