The Reproductive Behaviour of the Zebra Finch (Poephila Guttata), With Special Reference To Pseudofemale Behaviour and Displacement Activities

Abstract

The Zebra Finch (Poephila guttata) is a small Australian Ploceid which is ideal for the laboratory study of bird behaviour. Its attacking, fleeing, threatening and submissive behaviour are described and discussed. In this species there is no elaborate code of signals involved in this behaviour. Most disputes are settled mainly by actual fighting. This species builds a domed nest with a side entrance, the material for which is collected by the male. A special ceremony exists which apparently serves to strengthen the relationship between a pair in relation to a particular nest or nest-site. The pre-copulatory behaviour is described and analysed. The courtship of the male consists of an upright pivoting dance, during which it always sings and advances towards the female. The courtship of the latter takes the form of a horizontal body posture accompanied by a rapid quivering of the tail. The courtship of both sexes involves the three conflicting drives of attacking, fleeing and mating. In different species, the relative importance of these three drives will vary. In the Zebra Finch, the main conflict in pre-copulatory behaviour is between fleeing and mating. The female is more active than the male in incubating and rearing the young. The nestling possess brightly marked mouths which presumably facilitate feeding by the parents in the dark nest. Under certain circumstances, males were seen to perform the female courtship display and occasionally females responded with male behaviour, resulting in the occurrence of reversed mountings. The possible causation of this behaviour is discussed. It appears that the pseudofemale behaviour of the male is caused by strong sexual thwarting (as a result of the unresponsiveness of the female) in combination with the arousal of the drive to flee. Displacement activities which occur in this species are enumerated and described. They include various comfort movements, sleep, feeding, mounting, foodbegging and nest-building. Some of these occur as True, and other as Apparent, Alternative Displacement Activities. In the case of displacement beak-wiping it is possible to analyse accurately the differences between the displacement activity and its autochthonous form. There are differences in orientation, amplitude, velocity, and in the number of wipes per wiping-bout. This last difference is analysed quantitatively. Various other aspects of the reproductive behaviour are briefly mentioned, particularly the nature of territory and the strength of the pair-bond. The family Ploceidae show many degrees of socialisation and the defence of the territory by the Zebra Finch is often spasmodic, except when actually rearing young. The occurrence of attempted rape, when a new female is introduced, is discussed and the durability of the pair-bond after separation is investigated. A Redirection Activity is recorded, namely redirected mounting. A possible reason for the complexity of the markings of the Zebra Finch is discussed. Many of the component markings of the species are shared with various other Australian Grassfinches, and the demands of specificity can only be met by a unique combination of a number of these markings.