Regional song dialects of the Ruby-crowned Kinglet

. We used archived recordings of Ruby-crowned Kinglet ( Corthylio calendula ) songs to examine characteristics of the song, repertoire size, and regional dialects across the species’ breeding range and to assess possible cultural evolution in dialects. Using recordings of 313 individuals, we confirmed that individuals have a single song type and that there are distinct regional song dialects. Our examination of phrases that form the last of this species’ 3-part song revealed 43 different phrase types. We defined seven regions based on geographic features, ecoregions, and obvious clustering of particular phrase types. An eighth region corresponded to the published range of the subspecies C. c. grinnellii , coastal southern Alaska and the British Columbia coast. In each of those regions, two to three phrase types dominated and were found exclusively or primarily within a single region. Our finding of regional dialects confirms that the song of the Ruby-crowned Kinglet is, at least with respect to this phrase, learned rather than innate. In species, such as this kinglet that sing during migration or in their non-breeding range, mapped dialects can help reveal migration strategy and migratory connectivity. Monitoring changes in dialects over time can confirm cultural evolution and shed light on both the timing and location of song learning. RESUMEN