Meeting Abstract
Vocal signals convey information about affiliation, aggression, sexual state, and the identity of an individual. Variations in song structure across populations of the same species, known as dialects, have been described in frogs, birds, and mammals. The Ecuadorian Hillstar (Oreotrochilus chimborazo) is a hummingbird species in which males produce a high-frequency (HF) song (7-16 kHz) which consists of frequency-modulated introductory motifs followed by a series of trills. We investigated the variation in song structure of the HF song in this species to determine whether O. chimborazo exhibits dialects. We examined 8 populations along the Ecuadorian Andes, covering both subspecies, O. c. jamesonii and O. c. chimborazo. We found four dialects characterized by differences in the introductory motifs. The dialect found in the northern populations of O. c. jamesonii consists of an introductory whistle at ∿10 kHz, followed by a frequency-modulated introductory motif and trills at higher frequencies. The second dialect belongs to the subspecies O. c. chimborazo. Unlike the former, this HF song lacks the introductory whistle but instead, it exhibits two introductory motifs at ∿14.6 kHz. The third and fourth dialect songs are found in the two southern populations of O. c. jamesonii. These dialects differ from the others in the structure and number of introductory motifs. Although our findings map onto the microsatellite variation of the species, we found greater variability in the HF song than that present in the microsatellite analyses. These findings suggest that dialects may be the result of genetic variation and cultural evolution in the Ecuadorian Hillstar.
