CONICET | Buscador de Institutos y Recursos Humanos

Interspecific responses to vocalizations betweencoexisting species may reflect underlying ecological interactions. We examinedvocal interactions between sympatric Laterallusleucopyrrhus and L. melanophaiusin the coast of the Río de la Plata. They occur in different but adjacenthabitats with minor overlap and their loudsongs (trills) are very similar.Hence we asked, how do they respond to homo and heterospecific playback? We carriedout 192 playback trials over a year, 96 in typical L. leucopyrrhus habitat (Pajonal of Scirpus giganteus) and 96in typical L. melanophaius habitat (Matorralribereño). Eachhabitat was sampled twice per season (once with playback of each crake) duringthe four seasons. We placed 12 playbackpoints per habitat and recorded responses inside a 25m-radius. Playback responsesto homo and heterospecific playbacks were statistically the same for bothcrakes (P-values>.05; WilcoxonMatched Pairs Tests). These interspecific interactions seem to indicateinterspecific territoriality due to (1) an incidental effect of similarities invocalizations, or (2) an adaptation to reduce interspecific competition betweensympatric species with similar ecological characteristics. Future studies shouldtest these proposals by assessing responses to homologous vocalizations withvery different sound characteristics, such as contact or aggressive calls, and bymeasuring detailed variables in playback responses.