A COMPARATIVE STUDY OF THE COURTSHIP OF CERTAIN FINCHES (FRINGILLIDAE)

Abstract

Summary. The aggressive and courtship behaviour of captive individuals belonging to eight species of the Fringillidae was studied. The agonistic behaviour is described: the head‐forward threat posture, found in all these species, occurs also in other families and is probably primitive. The courtship behaviour of each species is described. During courtship, each bird tends to behave in three incompatible ways‐to attack, flee from and behave sexually towards its mate. Each courtship pattern is associated with a certain range of strengths of theae three tendencies. (The sense in which “tendency” is used, and the methods by which tendencies can be assessed, are discussed.) The seasonal changes in behaviour as the time of copulation approaches are traced for each species. In most (probably all) cases the male is usually dominant in winter, but, as his tendency to behave sexually increases, his tendency to attack his mate decreases and to flee from her increases. The female's behaviour changes similarly, but later in the season and less than the male's. The female is thus able to become dominant for much of the pre‐copulatory period. This inversion of dominance is most marked in the Chaffinch. At copulation both sexes of all species have strong tendencies to flee and to behave sexually, but rarely attack. In all the species studied (except perhaps the Bullfinch) the early courtship displays of the male are modified forms of the head‐forward threat posture. Such displays are sometimes associated with attacks on the female, but in other cases the male has a strong tendency to flee and his body is oriented obliquely or laterally to her. Each display can be analysed into a number of components‐wing‐raising, flufling, crouching, etc. Each such component may occur in many different postures, but is (nearly) always associated with the same tendency (attacking, fleeing or behaving sexually). Much of the variability in the postures is thus related to variations in the associated tendencies which result in different components being present and/or emphasized. The relationship between particular components and particular tendencies holds not only for the different displays of one species, but (at any rate for most components) for all the finch species studied. Courtship feeding is a ritualized displacement activity, though there is no certain evidence that it ever depended on conflicting tendencies. It probably promotes habituation to the proximity of the mate, hence facilitating copulation and reducing aggressiveness between the pair in the parental phase. Except for nest‐building in Canaries and Greenfinches, other ritualized displacement activities are apparently not important in the courtship of any of the species studied. Species‐characteristic differences between male and female behaviour affect all phasesof reproductive behaviour, and do not lie in the independent elimination of particular patterns from the repertoire of either sex. Sex differentiation in colour pattern is roughly correlated with that in behaviour. Morris's (1954) explanation of “pseudo‐female” behaviour in terms of “sparking over” is discussed. The behavioural evidence indicates that Greenfinch and Canary are very closely related, and that Chaffinch (and perhaps Brambling) are not closely related to the Carduelines.It does not, however, support Tordoff's (1954) suggestion that Fringilla is more closely related to buntings than to Carduelines, or that Carduelines are very closely related to the Estrildines. The functions of courtship behaviour are considered.