e analyzed the song pattern of the black redstart (Phoenicurus ochruros) from the Haibei area and compared it to three other recording sites on the Tibet Plateau using the Avisoft-SAS Lab program. Five extracted functions identified individuals from the Haibei population. By comparing populations from the Tibet Plateau (China), Slovakia (Central Europe), Germany and other sites in Europe, we established that the maximum song frequency was lowest in the Haibei population of the Tibet Plateau. On a large geographic scale, song differences increased with geographic distance. Black redstarts sing lengthy songs composed of two parts in both the Tibet Plateau and in Europe. However, while these two sections were totally or partly identical within the Tibet Plateau population, they were totally different in European populations. Redstart songs in the Tibet Plateau share a syllable of scrunching sound, while European individuals have a homologous section composed of repeat elements.
We examined the song sharing and variation pattern of 44 Anna’s hummingbird males at syllable level in San Francisco, California. Full songs of Anna’s hummingbird were composed of repeated blocks of phrases. Each male sang from three to six syllable types and syllable repertoire size averaged 5.1. A total of 38 syllable types were identified in songs of the population examined, which can be classified into five basic syllable categories. Each syllable category exhibited different variability among individuals. We quantified the variation of each category and found the variability was highest in the first phrase of song. Using Jaccard’s similarity coefficient, we found the syllable sharing among birds was significantly greater within one sample site than between sites. Using Mantel tests, we demonstrated that syllable sharing among birds tended to decline with the increase of inter-individual geographic distance. A microgeographic song variation pattern that nearest neighbours tend to sing more similar songs than non-neighbours was supported in these analyses. However, hierarchical cluster analysis suggested not all individuals singing the most similar songs were nearest neighbors. It might be due to possible postbreeding immigration and song learning pattern that syllable is a unit of learning in this species.
Vocalizations of the plaintive cuckoo (Cacomantis merulinus) and brush cuckoo (C. variolosus) were compared. Six major sound types were identified in the plaintive cuckoo, and four in the brush cuckoo. On the basis of song similarity as assessed by sonogram qualitatively and quantitatively, the grey-bellied cuckoo (C. passerinus) was considered conspecific with C. merulinus and the rusty-breasted cuckoo C. sepulcralis was considered conspecific with C. variolosus. The song similarities between C. merulinus and C. variolosus were considered homologous and derived from common ancestry.
The paper reported vocalizations of endemic Tibetan Plateau steppe sparrow, red- necked snow finch (Pyrgilauda ruficollis) by using SAS-Lab Pro. The subject similarity contrast and multivariate contrast were used to study the complexity and stability of sounds. The results indicated that songs of P. ruficollis were highly complicated with varied song types, song phrases, song syllable and combination of them. One song syllable shared by snow finches (Montifringilla nivalis henrici, M. adamsi, P. ruficollis and P. blanfordi) was selected as indicator to compare the taxonomic relationship among them. The similarity contrast and cluster analysis through SPSS were conducted to construct the similarity tree based on this shared syllable’s acoustic parameters including the highest frequency (HF), the lowest frequency (LF), the main frequency (MPF) and duration (DUR). The results revealed that the syllable similarities are accordant with taxonomic status suggested in previous studies based on morphologic, ecological and molecular analysis methods. The syllable shared by these snow finches were presumed to be homologous and derived from a common ancestry. Further studies on songs encoding phylogenetic signal of snow finches are needed.