DOI: 10.5061/dryad.1c59zw3xn
title: Hummingbird Plumage Color Diversity Exceeds the Gamut of all other Birds

description: 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.
description: Spectra in this dataset were collected from
 study skin specimens from the Yale Peabody Museum (YPM) and the American
 Museum of Natural History (AMNH). They were measured with a S2000 Ocean
 Optics spectrometer and a bifurcated fiber with an Ocean Optics
 DH-2000-BAL deuterium–halogen light source (Ocean Optics, Dunedin, FL) in
 a dark room with an integration time of 100 ms. We did not use a metal
 block to hold the reflectance probe because it can be difficult to
 accurately measure plumage reflectance peaks from small iridescent patches
 at a normal angle of incidence to the plumage surface. Rather, we used a
 Keysight 3D Probe Positioner (N2787A, KEYSIGHT, Santa Rosa, CA) to hold
 the optical fiber stable at the appropriate angle of incidence to maximize
 peak reflectance and saturation while maintaining peak reflectance below
 100%.  We measured six standardized
 patches from all specimens: crown, back, tail, wing, belly, and throat.
 Additional patches were measured if they were distinct to the human eye
 and large enough to measure reliably. Each plumage patch was measured from
 a different position three times. Multiple measurements were not averaged
 to prevent flattening of highly saturated peaks with slightly different
 hues. If a patch showed a gradient in color, measurements were taken at
 the ends and center of the gradient.  Each color patch was scored with a presumed color
 production mechanism, including barbule structural color, melanin (further
 classified as either eumelanin or phaeomelanin), or white (unpigmented).
 Color production mechanisms were inferred based on previous literature,
 visual appearance, and the shape of the reflectance spectra. Any color
 that showed barbule structural color as well as melanin was categorized as
 a barbule structural color. Structural black colors were excluded from
 analyses. Spectra data were combined and converted from individual reflectance spectrum data .txt files to species spectra .csv files (with all the spectra for each species examined) using the R code provided.
description: Please refer to readme file (README.docx)
 included on how to read the label for each spectra in the total
 hummingbird data dataset (Hummingbird Spectra final). The R-script allows for the creation of files that
 include all the spectra for a given species from individual spectrum
 files. We have included example spectrum text files to practice with. To
 use this R-script, spectrum files should be names according to the
 following:  A.beryllinaY21435(backlower)male.s_Reflection_1.txt S.genusID#(patchtype/location/identifiers)sex.s/m/w_Reflection_#ofmeasuremnt Note: s/m/w refer to presumed coloration mechanism (structural/melanin/white We analyzed this dataset using ​​the shareware computer program TetraColorSpace 1. 0 for MATLAB (Stoddard and Prum, 2008). TetraColorSpace software is available online at https://www.marycstoddard.com/software Stoddard, M. C. & Prum, R. O. Evolution of avian plumage color in a tetrahedral color space: a phylogenetic analysis of new world buntings. The American Naturalist 171, 755-776 (2008).