The importance of visual, vocal and behavioural cues for song tutor choice in Zebra finches

Abstract

This thesis examines the importance of visual, vocal and behavioural cues for song tutor choice in zebra finches, Taeniopygia guttata. Zebra finch males normally copy song at 35 to 65 days of age. In the wild the young become independent at about 35 days of age and form small flocks in the area of the colony where they will be exposed to a variety of song tutors. In Chapter 3 captive zebra finches are provided with the opportunity to learn from two conspecifics at 35 days of age. Female-raised males which are housed with two unrelated tutors prefer to learn from the one who is, most aggressive towards them. Normally-raised males which are housed with an unrelated tutor and one, whose song is similar to the father's tend to copy the tutor with the similar song: this relies on the young bird learning some characteristics of his father's song before independence. Chapter 4 shows that males and females can discriminate between their father's song and those of other males. Visual, vocal and behavioural cues are all important for species-specificity. Cross-fostering using Bengalese finches, Lonchura striata, as foster-parents is an important tool for studying this. Chapter 5 looks at Bengalese finch song development; Chapter 6 compares song development in cross-fostered zebra finches and Bengalese finches. Visual cues are important for tutor choice and young males of both species which are provided with a zebra finch singing Bengalese song and a Bengalese finch singing zebra finch song prefer the conspecific tutor (Chapter 7). Chapter 8 suggests that conspecific song elements are not important for zebra finches: there is no tendency to prefer a tutor with normal song over one singing Bengalese song. Cross-fostering can also, influence the timing of song learning. Males which are housed successively (Chapter 9) or simultaneously (Chapter 10) with both species tend to reproduce song which they heard before independence in addition to learning from the tutor which they heard after independence at 35 to 65 days of age: this indicates that the timing of the sensitive phase is flexible and mediated by both experience and age. There are a number of similarities between song learning and sexual imprinting which are discussed in Chapter 11. Crucial to these studies is a knowledge of the two species' behaviours. Chapter 12 compares, parental behaviour in captivity. Chapter 12 concludes with a plea for more research in the wild.