Meeting Abstract
P1.4 Friday, Jan. 4 Low-amplitude song: a meta-analysis of its prevalence and functions in North American birds WELKLIN, J.F.*; REICHARD, D.G.; KETTERSON, E.D.; Indiana Univ.; Indiana Univ.; Indiana Univ. jwelklin@indiana.edu
Research on birdsong has focused primarily on species’ high amplitude, long-range songs. Yet, the vocal repertoires of many avian taxa extend beyond those signals that are easily recognized from a distance by the human ear, and attention has recently turned to more enigmatic, low-amplitude vocalizations. Researchers studying the functions of these songs and calls have largely interpreted them as mediating aggression between males. However, males also produce low-amplitude vocalizations while interacting with females, raising the possibility that these songs may serve multiple functions including courtship, depending on the species sampled. Using the Birds of North America Online Archive, we performed a systematic search for evidence and presumed functions of low-amplitude vocalizations in the accounts of 749 bird species known to breed in North America. Using keywords such as: soft, quiet, low-amplitude, whispered, and strangled, we discovered 122 species that sing low-amplitude songs, and 301 species that produce low-amplitude calls. Of these 423 species, presumed courtship or territorial functions were reported for 138. Further, we found that more than twice as many species produce low-amplitude songs in male-female contexts (31 species) as compared to male-male contexts (12 species). These data suggest an important role for low amplitude vocalizations in courtship. Given how few low-amplitude vocalizations have a known function, and how even fewer of these functions are supported by experimental evidence, our survey highlights the need for future work investigating the occurrence and function of low-amplitude vocalizations. It also suggests that contrary to the current view favoring an aggressive function for low-amplitude songs, their role in courtship merits more attention.
