Song variation and persistence of song neighborhoods in a lekking hummingbird

Abstract

Recent studies reveal that hummingbirds' songs are more variable and complex than previously realized. The Wedge-tailed Sabrewing (Campylopterus curvipennis) forms leks composed of small adjacent territories defended individually from intruders. When females visit these territories, males emit long songs composed of structurally complex syllables. Their elaborate acoustic signals are intriguing because most species of lekking hummingbirds studied in detail have relatively simple and stereotyped songs. Here we report song variation among territorial males at one lek over 4 years. Despite variation in syllable composition, cluster analyses classified songs of territorial males into three groups ("song neighborhoods"), and the pattern of clustering was consistent over time. Song neighborhoods were also clustered spatially. The syllabic composition of songs from members of a given neighborhood was relatively constant from year to year, suggesting site and territory fidelity, and introductory syllables were emitted consistently as the signature of a group. Our findings demonstrate the existence (and persistence) of song neighborhoods in a lekking hummingbird. This spatial structure might result from reduced competition among males to occupy a territory for singing, kinship between members of a neighborhood, and/or as a consequence of sexual selection. Therefore, documentation of song neighborhoods shouldbe considered more often in future studies of song variation in hummingbirds that breed in leks. © The Cooper Ornithological Society 2009.