I am studying how an animal’s ecology and signaling environment shape the evolution and diversity of signals. The bulk of my work in this theme has focused on color evolution in Paruild warblers. Warblers vary considerably in color among species, occur throughout a wide variety of habitats, ranging from pine forests to swamps to meadows, and differ in several ecological traits, such as migratory behavior and species overlap. I previously found that evolutionary changes in migratory distance were driving losses of female coloration in this group, contrary to previous theory on how sexual color differences were primarily driven by changes in male coloration (Simpson et al. 2015). I am currently studying how natural and sexual selection together drive color diversity by each acting on different aspects of color and continuing to explore other factors driving warbler color evolution.
Additionally, in collaboration with the Smithsonian Tropical Research Institute, I studied a neotropical songbird, the red-throated ant-tanager (Habia fuscicauda) in Panama and found spatial variation in ambient light and noise predicted variation in male color and song (Simpson & McGraw 2018).