160708.pdf.txt

Abstract

Human ancestors and birds have co-existed on earth for over six million years. Although early humans killed and consumed birds to survive, never before have so many bird species been seriously endangered as they are today, with one in eight birds currently threatened with extinction. One possible cause is human-induced climate change. Studies in recent decades have found that many bird species are decreasing in abundance, altering aspects of their phenology, shifting their distributions north, and demonstrating earlier first arrival dates in their migration patterns. Some studies forecast the impacts of climate change on bird diversity using predictive climate models, but the most concrete analyses use data collected throughout the 20th century because climate change is difficult to predict. This thesis standardizes and analyzes a previously unused dataset of bird observations recorded by Princeton ornithologist Charles Rogers to assess bird diversity along the East Coast in the early 20th century by comparing data from two time periods: 1904 -1905 and 1941-1942. For more than seventy years, Rogers recorded his observations in bird journals, and I use three key metrics gathered from them—first seen dates, monthly species richness, and overall bird abundance—to detect changes in bird populations over the 38-year period. The results demonstrate that the effects of climate change on bird populations are not a recent phenomenon. In the later time period, migratory bird species show earlier first seen dates, increased monthly species richness, and fluctuations in abundance of species and families. Further research using this dataset can improve the accuracy of predictive models that forecast the effects of climate change on bird populations in order to better inform bird conservation efforts worldwide.