Universal Features in the Singing of Birds Uncovered by Comparative Research

Abstract

Aside from some exceptions, songbird species differ in the structure of their singing and usually also in the size and performance mode their song repertoires. In the past, most studies concentrated on the species specific differences of singing, and thereby contributed to a better understanding of their diversity. In our approach, however, we focussed on the opposite perspective; i.e. we investigated whether and how far songbirds share structural song properties. To have a solid data base we focussed on four species of thrushes which were famous for their large vocal repertoires. The two Asian bird species were Oriental Magpie Robins (Copsychus saularis) and Shama Thrushes (Copsychus malabaricus), the two European species the Common Nightingale (Luscinia megarhynchos) and the Thrush Nightingale (Luscinia luscinia). The latter were incorporated into a sample 40 other European songbird species (Table 1) serving as a framework for our comparative approach (Figure 2, 4). Besides well-known differences among species, our analyses of song material yielded some remarkably similar relationships between structural and functional song properties, which often were shared even by unrelated species. In particular measures of song durations were usually related to song application during vocal interaction. And, individual variation of song duration was mainly a result of differences in syllable repetition within trilled song sections. Although some of these findings were predicted already by former studies (see Todt, 2004), their essentials can be based now on profound data sets of detailed measurement.Keywords: European Thrushes, Asian Thrushes, Copsychus saularis, C. malabaricus, song structure, signal lengths.doi: 10.3126/on.v6i1.1648Our Nature (2008)6:1-14