Vocal behaviour of the island-endemic Cozumel Wren (Troglodytes aedon beani): song structure, repertoires, and song sharing

Documenting the diversity of vocal behaviour across different avian taxa is key to understanding the ecology and evolution of complex behaviours. Unique to Cozumel Island in the Mexican Caribbean Sea, the Cozumel Wren (Troglodytes aedon beani) provides an opportunity to investigate how isolation influences complex cultural traits. Most aspects of the biology, natural history, and taxonomy of Cozumel Wrens are unknown. In an attempt to better understand the Cozumel Wren's biology, we provide the first description of the songs and the vocal behaviour of this island-endemic bird. Based on more than 700 h of recordings, including more than 36,000 songs, we describe the fine structural characteristics of male Cozumel Wrens songs, and explore patterns of repertoire organization and song sharing. Cozumel Wrens sing songs composed of highly variable syllables, with prominent trills at the end of each song. Each bird has a limited repertoire of songs, which they create by recombining a restricted number of syllable and trill types. They repeat a song type several times before switching to a different one, with some variation in the number of times they repeat specific elements. Cozumel Wrens share more song types with neighbours than distant individuals. Syllable sharing, however, is equivalent between neighbours and distant individuals. Our results provide important data for future research on the ecology, evolution, and behaviour of this island-endemic songbird, and for helping to clarify the taxonomic status of Cozumel Wrens.