First Advisor

Benedict, Lauryn

First Committee Member

McGlaughlin, Mitchell

Second Committee Member

Hamilton, Marian

Degree Name

Master of Science

Document Type

Thesis

Date Created

11-2025

Department

College of Natural and Health Sciences, Biological Sciences, Biological Sciences Student Work

Abstract

Vocal learning is a trait unique to humans, bats, cetaceans, primates, and birds (Jarvis & Nottebohm, 1997; McComb & Semple, 2005; Wilbrecht & Nottebohm, 2003). Although there has been extensive research on vocal learning in songbirds, parrots are an even closer proxy to human learning, as they are social, intelligent, and lifelong learners, with some having repertoires of over 300 sounds (Benedict et al., 2022; Péron et al., 2011; Thomsen et al., 2019; Toft & Wright, 2015). Elevated vocal learning can be attributed to the need for parrots to have strong communication skills through the sharing of information over foraging, roosting, rearing young, and territory defense (Cockburn, 2006; Toft & Wright, 2015). There are some predominant overarching hypotheses as to how vocal learning evolved. Did it evolve as an adaptation to environmental attributes like communal signaling, diet, flock size, and habitat density (Carouso-Peck et al., 2021; Nowicki & Searcy, 2014)? Is it a parallel of sexually selected traits like color elaboration (Chen et al., 2012)? Or is vocal learning evolutionary promoted by physical traits like brain size, mass, and longevity (Ah-King, 2022; Jarvis, 2006; Riebel, 2003)? My thesis aimed to answer two questions: “Is vocal learning phylogenetically conserved?” and “Do the reported vocal mimicry repertoires of companion parrots (Psittaciformes) coevolve with species-level environmental, sexual, and physical characteristics?”. The purpose of this study is to use phylogenetic comparative methods in R to test eight environmental, color, and physical traits against vocal repertoire data from companion parrots and determine which coevolve with vocal learning abilities. My results showed a strong linkage between physical traits and the evolution of vocal learning, specifically that species with larger brains, larger bodies, and longer lifespans have larger learned repertoires. This supports the idea that vocal learning is not environmentally driven or a product of sexual selection but is a trait of larger species with longer lifespans and bigger brains. Using this information, we can continue to test known traits with vocal learning data to determine how this unique ability evolved not only for parrots, but other vocal learners as well.

Abstract Format

html

Disciplines

Behavior and Ethology | Evolution

Keywords

Phylogenetics; Parrot; Vocal Learning; Evolution

Language

English

Extent

88 pages

Rights Statement

Copyright is held by the author

Digital Origin

Born digital

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