HAHN, T. P. *; KELSEY, T. R.; PEREYRA, M. E.: Geographic variation in flight calls of a nomadic cardueline finch, the evening grosbeak (Coccothraustes vespertinus).

Many species of oscine songbirds display vocal variation in the form of song dialects. Variation in non-song vocalizations, or calls, is less familiar. Calls, unlike song, are often thought to be innate and relatively invariant among individuals. These generalizations may be far less accurate than suspected. Acoustic features of some calls are learned in several species. Further, variation in calls may be common, and distributed in interesting geographic and/or population-specific patterns, similar to song dialects. This is turning out to be particularly evident in the cardueline finches (canaries, goldfinches, etc). Here we discuss published data on call learning and call variation in several carduelines, and present new data demonstrating discrete “call types” in the evening grosbeak (Coccothraustes vespertinus). Evening grosbeak flight calls are simple frequency-modulated chirps. We have found five forms of this flight call, four in western and one in eastern North America. Though only three subspecies of evening grosbeaks are currently recognized, the geographic distribution of the five flight call forms matches the ranges of five formerly-recognized subspecies. However, like many other carduelines, evening grosbeaks are nomadic, and it is not unusual for two vocal forms to coexist. We do not yet know whether evening grosbeaks learn flight calls, but several other carduelines do. Cardueline finches appear to be particularly tractable for studying call learning and geographic or inter-population call variation. They also may help reveal the role of culturally-transmitted traits in evolution and maintenance of new taxa when geographic isolation is limited, intermittent, or lacking.