The Origins of Music: Preface - Preface

its repertoire size is no easy matter,but Kroodsma and Parker (1977)

solved the problem in an ingenious way by taking every hundredth song

in a sample of 4,654,and looking to see if it recurred anywhere else in

the whole sample.There were 45 different song types among the 46

examined,and they accounted for 116 of the songs in the whole sample.

In other words they were repeated an average of 2.6 times each.The

repertoire of the bird could therefore be estimated as 4,654/2.6 =1,805.

To illustrate the diversity of singing birds,we will now consider six case

histories,two birds with small repertoires and four with large ones.

Small Repertoires

Chaffinch

The way in which chaffinches (Fringilla coelebs) use their songs was

studied particularly by Hinde (1958) and Slater (1983).Most chaffinches

have two or three song types,although some have only one and others

may have up to six.Each song type is fixed in form and consists of exactly

the same sequence of syllable types every time it is produced,although

syllables in the trill part of the song may be repeated a varied number

of times.Two songs within the repertoire of a single bird can be quite

similar,although with practice they can usually be distinguished by ear.

The chaffinch is typical of a species with a small repertoire that sings

with what is called eventual variety.A male with more than one song

type will sing a whole series of one type before switching to another.If

he has three or four types,he will usually sing a sequence of each in turn

before returning to the first again,although not necessarily always in the

same order.It is also quite common for one song to be a much larger

part of a bird’s output than another.Indeed,a song type may be so rare

that it puts in only an occasional appearance.

Whereas all these features may not be true of other species,it is cer-

tainly common for birds with small repertoires to sing with eventual,

rather than immediate,variety,such as the great tit (Krebs 1976) and

western meadowlark (Sturnella neglecta;Falls and Krebs 1975).Such

redundancy is likely to function to ensure that each song gets through to

the hearer and is fully received and understood.Singing in this pattern

is likely to have evolved primarily in the context of male-male encoun-

ters,where song matching is a common phenomenon.

Grace’s Warbler

Grace’s warbler (Dendroica graciae),in the southwestern United States,

also has a small repertoire of song types,but uses them in a different way

from the chaffinch (Staicer 1989).One or two songs in a bird’s repertoire

53 Birdsong Repertoires

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