The Development of Song in the Blackbird Turdus Merula

SUMMARY An analysis is made of the song of one wild Blackbird in 1957 in south Oxfordshire. An arbitrary classification of the song phrases is suggested. Sample recordings were made throughout the song period, and methods of analysis are described. The composition of the song at the beginning of the season is described. Reference is made to the “practising” habit, to the early formation of compound phrases and to a tendency to use certain phrases in particular contexts. 26 phrases, used at the outset of the season, constituted a basis upon which the developed forms were built. Five means of treating existing phrases were found: (1) whole phrases and extracts from phrases were combined to form new phrases; (2) new material was added to existing phrases; (3) notes contained within the phrase were repeated; (4) new terminal decorations were added to phrases; (5) phrase contraction by the omission of notes occurred. Phrases were organized into recurring series, many of which became permanent. Such organization of the song phrases, and the creation and extension of compound phrases, continued throughout the season. The influence of terminal decorations upon phrase order is noted. There was little evidence of disintegration of the song as the season ended. It was found that an increase in frequency of occurrence of developed forms was usually balanced by a corresponding decrease in the use of the phrases from which they were derived. Certain highly developed forms were used much more frequently than their related basic phrases. Infrequently used developed forms appeared to be of transitional character, while those that were not retained were replaced by new forms. The response to the song of another Blackbird is described. Counter singing, communal singing and antiphonal singing by the two birds were recorded. The scolding “churr” of a Blue Tit was copied and retained as a terminal decoration to a phrase. The mature song presented a distinct contrast to the early song. Manipulation of material rather than material as such was responsible for the song development. It is suggested that deliberate selection of material occurred. The song is discussed as a functional and an aesthetic activity and an attempt is made to correlate the two aspects.