Date of Graduation

Summer 2023

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Jay McEntee

Abstract

The Black-capped chickadee (Poecile atricapillus) and Carolina chickadee (P. carolinensis) are North American songbird species that hybridize in a narrow contact zone stretching latitudinally from New Jersey to Kansas, USA. The association between genetic ancestry and song type in this hybrid zone has been studied independently several times and found to be minimal or absent, likely due to the influence of cultural transmission on learned song in the oscine passerine clade to which the chickadees belong. Despite this, the song of both species remains remarkably distinct in allopatry, suggesting a genetic constraint on certain qualities of their broadly learned song. I conducted genetic and acoustic sampling in a small population of chickadees in the hybrid zone in western Missouri to address the question of whether song is related to genotype from a different angle than has been taken previously. I first genotyped 55 chickadees from hybrid zone, Black-capped, and Carolina populations in Missouri and Kansas to assess the local applicability of a commonly-used genotyping method for these species, and to generate genotype scores for Missouri hybrid zone chickadees. Using active recording methods, I then obtained high-volume, high-quality recordings of songs of 10 genotyped chickadees from one hybrid zone population. I used these data to generate multivariate measurements of song variety across three different dimensions for each individual. I tested how well, and in what direction, genetic ancestry predicted song variety for each of these dimensions, predicting that song variety would increase with increasing Carolina chickadee ancestry. Linear models predicting song variety in 2 and 3 dimensions from genetic ancestry had poor fit to the data, but slope values in the predicted direction. The linear model predicting song variety in 1 dimension, similar to measurements used to characterize song phenotypes in past studies, had the worst fit to the data and a slope value near 0. These results, while not conclusive enough to confidently suggest a role of genetic ancestry in song variety, provide support for the continued use of these novel multidimensional song variety measurements and offer future directions for tackling the question of the ancestry-song relationship in the chickadee hybrid zone.

Keywords

birds, hybridization, genetics, molecular markers, birdsong, bioacoustics, cultural evolution

Subject Categories

Behavior and Ethology | Evolution | Other Ecology and Evolutionary Biology | Population Biology

Copyright

© Shelby Madison Palmer

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