Effects of snowpack on avian abundance and species richness in Sierra Nevada forests

This thesis examined avian population dynamics over a four year span (2011-2014) in four forest types in Kings Canyon, Sequoia, and Yosemite National Parks, California. I asked, do bird populations show fluctuations in abundance and species richness depending on early spring snowpack levels in various forest types of the Sierra Nevada? I conducted point transect sampling surveys as part of the Sierra Nevada Network's Inventory and Monitoring bird monitoring program. To calculate local abundances for fourteen common bird species, I modeled detection functions in program Distance 6.2. I also determined species richness for each transect, and finally correlated avian abundance with spring snow depths. None of the common bird species in this study displayed a strong correlation between their abundance and snow depths in any of the four years. Clark's Nutcracker indicated potential for a positive correlation for abundance and snow depth, but this result may have been driven by other factors. With changing climate in the Sierra Nevada expected to increase the variability of snowpack among years, it is crucial to continue studying relationships between bird populations and snowfall in the Sierra Nevada.