Behaviour 2019
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Dialects in the High-frequency Courtship Song of an Andean Hummingbird
Fernanda / G Duque1, 2, Marco / F Monteros3, Carlos / A Rodriguez-Saltos4, Blessy Varghese1, Walter Wilczynski1, 2, Laura / L Carruth1, 2. 1Neuroscience Institute, Georgia State University, Atlanta, Georgia, United States; 2Center for Behavioral Neuroscience, Georgia State University, Atlanta, Georgia, United States; 3Instituto Nacional de Biodiversidad, Quito, Pichincha, Ecuador; 4Jackson School of Geosciences, Univ Texas at Austin, Austin, Texas, United States

The Ecuadorian Hillstar (Oreotrochilus chimborazo) is a hummingbird species in which males produce a high-frequency song (HF) (7-16 kHz) consisting of frequency-modulated introductory motifs and trills. This song is broadcast as a territorial signal to conspecific males and a courtship song to females. We investigated the variation in the HF song to determine whether O. chimborazo exhibits dialects. We examined 8 populations, covering both subspecies, O. c. jamesonii and O. c. chimborazo. We found four dialects characterized by differences in the total number of elements in the song and song duration. Moreover, each song variant has a unique trajectory of dominant frequency, so that different frequencies are emphasized throughout the song. Finally, our dissimilarity analysis showed that the northern dialect of the subspecies jamesonii, is the most divergent from the other three, while the dialects of the subspecies chimborazo and a neighboring southern population of the subspecies jamesonii are the most similar in the structure of the introductory motifs. Finally, the most southern variant is also the longest exhibiting the highest number of introductory motifs and trills.