Colorful plumage in birds is the result of pigments that selectively absorb light to produce yellow, orange, and red, and nanostructures that selectively reflect light to produce blue and violet. Pigments and nanostructures within the feather are increasingly well-characterized, yet many aspects of color production in feathers remain enigmatic and underexplored. I'm interested in how variation in feather microstructures (the microscale branches of the feather, called barbs and barbules) and feather macrostructure (the size, shape, and arrangement of feathers on the body) can enhance the colors produced by pigments and nanostructures within the feather. How do evolutionary changes in barbs and barbules alter feather color, and are microstructural modifications that enhance coloration constrained by selection for other feather functions? At the macrostructural scale, how do optical interactions among different layers of feathers shape overall plumage coloration, and does selection for coloration act on hidden layers of feathers in addition to visible, colorful layers of feathers? I'm using a range of imaging techniques (confocal and electron microscopy, multispectral and hyperspectral imaging, reflectance spectrophotometry and microspectrophotometry), optical modeling, and phylogenetic comparative methods to investigate these questions in tanagers and other birds.

Past projects and other interests