The Reaction of Great Tits (Parus major) to Playback of Degraded and Undegraded Songs: The Effect of Familiarity with the Stimulus Song Type

Abstract

We played degraded and undegraded song types to territorial Great Tits. Each bird was tested with degraded and undegraded renditions of a song type in its repertoire and of a song not in its repertoire. The birds responded less strongly to degraded than to undegraded songs, and the difference was significant only if the test song was of the same type as, or similar to, one in the bird's repertoire. These results are consistent with Richards' (1981) hypothesis that degradation cues are used to judge distance and Morton's (1982) idea that degradation may be judged by comparison with a standard consisting of the bird's own rendition of the song. We also found that birds are better able to discriminate between undegraded and degraded song types if their neighbors sing the song. The results are discussed in relation to hypotheses concerning song matching and neighbor-stranger discrimination.