Intra- and inter-specific vocal variation in three Neotropical cardinalids (Passeriformes: Fringillidae) and its relationship with body mass

GARCÍA, NATALIA CRISTINA; BARREIRA, ANA SOLEDAD; KOPUCHIAN, CECILIA; TUBARO, PABLO LUIS

EMU

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2014 vol. 114 p. 129 - 136

0158-4197

Several studies considering a large number of bird species have shown that song frequencies have a strong negative relationship with body size. However, mixed results were obtained at the intra-specific level or when comparing closely related species. Here, we compared the vocalizations of Cyanoloxia glaucocaerulea (which is monotypic), of three out of five subspecies of Cyanocompsa brissonii, and of the four subspecies of Cyanocompsa cyanoides. These species of Neotropical cardinalids and their subspecies differ significantly in their body size, thus we compared them all together to examine the allometric relationship with song frequencies, using body mass as a proxy of body size. The maximum frequency and the emphasised frequency, i. e. the frequency of highest amplitude of the song, showed the expected negative correlation with body mass, supporting the idea that the aforementioned relationship stands when comparing closely related lineages in members of the Cyanoloxia and Cyanocompsa genera. We also found that note duration, note rate and internote interval duration correlated with body mass: the heavier species had longer notes produced at a lower rate and separated by longer intervals. The correlation of temporal variables with body mass suggests that body size could also influence the temporal structure of song. Our findings point out the importance of considering the role of bird morphology when studying song evolution, even if differences are small, in both frequency and time-related variables.