A Quantitative Study of Parental Behaviour in the Bengalese Finch

This is a detailed account of the behaviour of Bengalese Finches during the period when young are in the nest. In addition to providing as complete a description of the behaviour as possible, the data are examined in order to obtain some understanding of the organisation of the behaviour both on the level of the individual and on that of the family. Quantitatively, the behaviour is strikingly variable. Changes in the behaviour of the parents during the brood, between hatching and fledging, were to be expected, but in addition there are individual differences in behaviour and also very great differences in the behaviour of the same individual with different broods. These variations are analysed and an attempt to determine their causes is made. Further, these variations - especially the differences among the broods of the same individual - are interesting not only from the point of view of causation but also in terms of the functioning of the system since they affect the survival of the chicks.