Date of Award
Annual survival, Autonomous recorder, Microdialect, Passive acoustic monitoring, Population size, Savannah Sparrow
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Bioacoustic monitoring provides an innovative technique for studying the behaviour and ecology of wild birds. In this thesis I use bioacoustic monitoring as a tool for studying Savannah Sparrows (Passerculus sandwichensis). In my first data chapter, I tested the accuracy of passive acoustic monitoring in estimating population size and annual survival in an island population of Savannah Sparrows. Six years of data reveal that passive acoustic monitoring with autonomous recorders provides accurate underestimates of population size and annual survival. I found that passive acoustic monitoring estimated population size with 74% accuracy, with higher accuracy in low density years. I also found that passive acoustic monitoring estimated annual survival with 80% accuracy, providing the first known study to use passive acoustic monitoring to estimate annual survival. In my second data chapter, I used passive acoustic monitoring to study patterns of geographic variation, focusing specifically on whether Savannah Sparrows exhibit a small- scale microdialect pattern of acoustic variation. I found that males sound more similar to their neighbours than to birds who were at least one kilometre away in the population. Using mark-recapture data, I show that males dispersed, on average, 189m from their natal site to their first breeding territory the following year. I suggest that vocal learning, combined with small dispersal distances and the process of overproduction and attrition, gives rise to microdialects. My results provide support for the accuracy of autonomous recorders in studying the ecology of wild bird populations and patterns of geographic variation in bird songs.
Hensel, Abby Lynn Jill, "Bioacoustic Studies of Population Size and Microdialects in an Island-Living Savannah Sparrow Population" (2021). Electronic Theses and Dissertations. 8873.