Geographic variation in the duets of the Rufous-naped Wren (Campylorhynchus rufinucha) complex

Acoustic signals used in animal communication play a key role in mate attraction, species recognition and territory defense. Variation in acoustic signals may reflect population structure, lack of gene flow, and phylogenetic relationships. In birds, the study of geographic variation in acoustic signals has been useful for elucidating potential factors involved in phenotypic divergence and for establishing species limits. However, most of the studies on geographic variation have focused on calls and solo songs, with few studies focusing on complex behaviors such as duets. In this study, we investigated the variation in the duets of the Rufous-naped Wrens (Campylorhynchus rufinucha). Our results suggest that duets vary across the distribution range of the species complex, matching the three taxonomic groups previously suggested (rufinucha, humilis and capistratus). We also found a marked song sexual dimorphism in two groups, rufinucha and humilis, that is lacking in capistratus. At the lo...