Fear in Many Voices: Evidence for Vocal Dialects in Palmchat Distress Calls

Abstract

The palmchat (Dulus dominicus) is a highly social bird with a robust multi-level societal structure that requires effective vocal communication between members. Geographic variation in vocalizations can lead to the emergence of vocal dialects between populations, a phenomenon that has not yet been studied in this species. This thesis examines whether vocal dialects exist between montane and coastal palmchat populations in the Dominican Republic. Palmchat distress calls were collected from Jarabacoa (montane) and Punta Cana (coastal) and later analyzed using both acoustic parameters and spectral components to visually and computationally classify calls by region. Results show significant divergence in the distress calls of the two populations, with calls clustering by region and classification analyses exceeding chance expectations. This work provides evidence for the presence of vocal dialects in palmchat distress calls.