Investigating impacts of environmental biotic and abiotic factors on the breeding habitat and diet of declining grassland birds
Advisor: Dr. Jinelle Sperry
Zoom link: https://go.nres.illinois.edu/AngellDefense
Grassland birds have been in precipitous decline in North America for over 50 years, primarily due to widespread habitat loss. To maximize the effectiveness of remaining grasslands, conservation will rely on a thorough understanding of how environmental characteristics influence breeding habitat quality. To holistically examine grassland habitats, I monitored the nests of four species, conducted vegetation surveys, sampled local arthropod communities, and collected fecal samples from nestlings to determine provisioned diet using DNA metabarcoding. Grasshopper sparrows placed their nests in areas with greater warm-season grass cover and deeper litter, which was associated with lower daily predation risk. All four species preferred to feed Orthopteran, Lepidopteran, and Aranean prey, while other orders were almost universally avoided. The composition of grasshopper sparrow nestling diets was best explained by yearly variation, which coincides with notable climatic differences. These results exhibit the importance of biotic and abiotic factors on grassland bird productivity and inform considerations related to management and climate change.
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