Meeting Abstract
Understanding the function of vocal dialects is a key interest of researchers interested in the evolution of culturally transmitted traits. However, the question of how these mosaic-like patterns of vocal variation become established in the first place has received less attention. One approach to addressing this gap is using recently established or actively expanding species as models of vocal dialect formation. The rosy-faced lovebird (Agapornis roseicollis) is a small parrot native to Namibia that began establishing feral populations in the Phoenix metropolitan area in the late 1980s. Since then, their total population has grown to an estimated 3,000 birds occupying 10 municipal areas. Their rapid growth and relatively recent invasion history make these populations an ideal model for understanding the conditions under which vocal dialects may evolve. The aim of our study is to identify whether geographically distinct populations of lovebirds display evidence of vocal dialects in their socially-learned contact calls. Over a 2-year period we collected contact calls from birds at 9 locations across a 2000 km2 area. Call similarity was assessed using spectrographic cross correlation followed by Mantel tests, and one-way ANOVAs performed using the results from a principle components analyses of 22 different acoustic parameters. ANOVA results indicate that some populations of lovebirds do differ significantly in their acoustic parameters with a pattern of increasing call similarity with geographic distance. Although further study is needed to understand the conditions that favor the differentiation of contact call structure in these populations, our results support the use of the invasive lovebirds as a model of vocal dialect formation and evolution.
