Hummingbird Plumage Color Diversity Exceeds the Gamut of all other Birds

A color gamut quantitatively describes the diversity of a taxon's integumentary coloration as seen by a specific organismal visual system. We estimated the plumage color gamut of hummingbirds (Trochilidae), a family known for its diverse barbule structural coloration, using a tetrahedral avian color stimulus space and spectra from a taxonomically diverse sample of 114 species. The spectra sampled occupied 34.2% of the total diversity of colors perceivable by hummingbirds, which suggests constraints on their plumage color production. However, the size of the hummingbird color gamut is equivalent or greater than the previous estimate of the gamut for all birds, making hummingbirds the most diversely colored family of birds known. Using one model of avian visual systems, our new data for hummingbirds increases the avian color gamut by 56%. Our results demonstrate that barbule structural color is the most versatile plumage coloration mechanism, achieving unique highly saturated colors with multi-peak reflectance.