Evolution of Hummingbird Coloration and Courtship Displays
Hummingbirds showcase some of the most brilliant colors in the animal kingdom and possess almost every color under the rainbow. These colors are primarily iridescent, meaning their appearance is based on the angles at which they are illuminated and observed. The angle dependence of iridescent coloration allows hummingbirds to dynamically manipulate their color appearance through behavioral displays that alter their position and orientation relative to the environment (i.e. sun) and receiver (i.e. females). I am working to understand how hummingbird iridescent coloration and courtship displays interact with each other and the environment and how these traits (and their interactions) evolved. On my youtube channel, you can find examples of displays from the species below.
From left to right: Black-chinned, Broad-tailed, Allen’s, Calliope, Costa’s, and Anna’s hummingbirds (displays from side, displays from below).
Broad-Scale Patterns of Color Evolution
I am also working to understand how coloration evolved in several groups of taxa. Color evolution can be influenced by several factors such as the mechanism of color production (e.g. carotenoids), natural selection pressures (e.g. predation, energy expenditure), or sexual selection (e.g. female choice, intra-sexual competition). For example, I have found in wood-warblers that differences in coloration between males and females has been driven by the distances each species migrates. I have also helped uncover the ordered evolutionary pathways of carotenoid pigments (responsible for red, oranges, and yellows in most birds) in finches, and am currently studying the evolution of coloration in hummingbirds and jumping spiders.
Environmental Influences on Multiple Signals
The environment influences signals, such as coloration and behavioral displays, in many ways. In a tropical passerine, the red-throated ant-tanager, I found that both ambient noise and light on a male territory predict aspects of that male’s song and coloration. I currently working to understand environmental influences on the appearance of hummingbird coloration and the anthropomorphic effects of night lights on quail behavior and coloration.
Other Color and Behavior Based Research
Animals, in general, display a great diversity in coloration and behaviors. I am interested in studying coloration and behaviors of all forms, and have started exploring the mechanisms and functions of these traits in peacocks, grasshoppers, beetles, Gila monsters, and penguins.