DIFFERENCES IN THE ORGANIZATION OF SONG REPERTOIRES IN TWO LEAF-WARBLER SPECIES (PHYLLOSCOPIDAE): LARGE-BILLED LEAF WARBLER (PHYLLOSCOPUS MAGNIROSTRIS) AND SULPHUR-BREASTED LEAF WARBLER (PHYLLOSCOPUS RICKETTI)

摘要

Some song types composing the repertoire of males and organization of singing in two leaf warbler species from China large-billed leaf warbler and sulphur-breasted leaf warbler are considered. Both warblers have a repertoire of the similar "archetype" and simple song types (5-9 notes). The repertoire size is 6-7 song types in large-billed leaf warbler and 8-9 types in sulphur-breasted leaf warbler. The time and frequency parameters of five notes in each song type were measured in both species. Euclidean distances between all song types from the repertoire of a given male or a species were calculated. Songs of large-billed leaf warbler males were more similar (according to Euclidian distance) than those of sulphur-breasted leaf warbler males. Large billed leaf warbler males more often switched songs during singing. The correlation between the rate of switching the song type and the mean Euclidian distances between all song types from the repertoire of a particular male was found to be negative. This pattern appears to reflect the signaling function of songs, because two similar song types carry less information than two dissimilar song types.