The Origins of Music: Preface - Preface

seem to be a random outpouring is in fact highly organized (Eens,

Pinxten,and Verheyen 1989,1991b).A bout of singing lasts an average

of twenty-five seconds and consists of a sequence of phrases or song

types with very short intervals (mostly less than 0.1 second) between

them.Each phrase tends to be repeated several times before the bird

moves on to the next.Repertoire size varies:among twenty-seven males

it ranged from twenty-one to sixty-seven song types (Eens,Pinxten,and

Verheyen 1991b).

The order of song types within a bout of singing is relatively fixed.

Types fall into four broad categories,which also tend to occur at partic-

ular points in the sequence:

1.The bout normally starts with a number of whistles,each male having

a repertoire of seven to twelve (Hausberger and Guyomarc’h 1981).

2.The second section consists of a series of variable and complex

phrases including cases of mimicry;each male has fifteen to twenty dif-

ferent imitations in his repertoire (Hindmarsh 1984).

3.The third part of the bout consists of rattle song types.These phrases

include a rapid succession of clicks sounding like a rattle,and each male

has a repertoire of two to fourteen of them.

4.Most song bouts that are not interrupted earlier end with some loud,

high-frequency song types;a male may have up to six of these.

Again,as with the nightingale,starling song may seem endlessly varied

to the ear,but closer analysis reveals that each male has a limited reper-

toire of types and that these are ordered according to quite well-

specified rules.

Marsh Warbler

Most birds learn only the song of their own species.The fact that they

are reared by,and normally imprint upon and develop social relations

with,members of that species is one reason for this.But some species,of

which the starling is one,usually include imitations within their song.

Given the rarity of improvisation among birds,the best guess is that this

is a way in which males can enhance the variety,and hence the attrac-

tiveness,of their songs.

One of the most remarkable cases of mimicry,which forms a good case

study,is that of the European marsh warbler (Acrocephalus palustris)

studied by Dowsett-Lemaire (1979).This species breeds in Europe and

migrates to East Africa.Young birds are thought to learn their song

entirely in the first few months of life.They cannot base it on other

members of their own species,as adult males cease to sing before their

chicks hatch.Instead,Dowsett-Lemaire estimated that each young male

56 Peter J.B.Slater

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