Food Availability Influencing Songbird Fitness in Urbanized Landscapes
AuthorTran, Jacquelynn P.V.
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Urbanization can have negative impacts on wildlife diversity through habitat destruction and threats to dependable food sources. In this study, we investigate caterpillars, a food source birds rely on to feed their young, and their abundance patterns. We aimed to determine whether urban areas experience earlier caterpillar peak seasons than rural sites and if this may be correlated with differing vegetation types and lesser House wren (Troglodytes aedon) fledgling viability. We compared data from one rural and two urban field sites around the Reno, Nevada metropolitan area collected in April - July 2019. We found that our urban site experienced a greater caterpillar abundance and earlier caterpillar peak seasons. Wren fledglings at urban sites also weighed less than rural fledglings. Our study strongly indicates that earlier caterpillar peaks in urban sites led to smaller fledgling weights. While we found differences in vegetation composition between our rural and urban sites, it might be more useful to look at leaf emergence to compare that with the timing of caterpillar peaks. We suggest that further study should be done on leaf emergence and possibly on parental provisioning rates, to provide more insight on this tri-trophic interaction.