DOI: 10.5061/dryad.5tb2rbpdt
title: Climate underpins continent-wide patterns of carotenoid-based feather color consistent with Gloger’s observations

description: Animal coloration has long been predicted to vary across geographic and
 climatic gradients in accordance with a longstanding ecogeographical rule.
 But further to his widely supported predictions that melanin pigmentation
 increases towards the Equator, Gloger observed that reds and yellows are
 more vivid in warm regions and thus more prevalent at lower latitudes, a
 prediction supported further by Görnitz who suggested these colors would
 be more intense in areas with higher rainfall. Yet, studies of the
 associations between geography or climate and carotenoid-based plumage
 coloration to test these observations at a continental scale are scarce.
 Here, we investigated the extent to which yellow and red feather color
 vary according to these hypotheses in Pogoniulus tinkerbirds with
 distributions across sub-Saharan Africa. We tested first for associations
 of feather color with geography along latitudinal or elevational
 gradients; and then for associations with the climatic factors of rainfall
 and temperature that may underpin color variation on continental scales.
 We find evidence consistent with Gloger and Görnitz’s observations; that
 more saturated colors and warmer hues at lower latitudes were primarily
 attributed to a relationship of underpart color with temperature and
 rainfall. By contrast, forecrown color, a trait previously associated with
 sexual selection, had a more complex association with geography and
 climate, with red forecrown hue associated with rainfall, but yellow
 intensity showing contrasting patterns with latitude. We highlight the
 complex nature of carotenoid-based plumage coloration, suggesting that
 although environmental factors affect the abundance of carotenoid
 availability, plumage coloration is also influenced by other selective
 pressures.
description: # Climate underpins continent-wide patterns of carotenoid-based feather
 color consistent with Gloger’s observations
 [https://doi.org/10.5061/dryad.5tb2rbpdt](https://doi.org/10.5061/dryad.5tb2rbpdt) ## Description of the data and file structure This README file was generated on 2025-02-10 by Sifiso M. Lukhele **Overview** This supplementary dataset contains data to reproduce the results of our research paper. It contains metadata that includes localities of museum specimens and computed color variables with reflectance spectra measured from the belly, breast, rump, and crown patches of Pogoniulus* tinkerbirds. ### Files and variables #### File: Lukhele\_et\_al\_2025\_PogoniulusMuseumData\_ColorVariation.xlsx **Description:**  ##### Variables * Brightness - computed as the mean percentage reflectance over the entire reflectance spectrum for the measured feather surface (mean brightness: B2 in pavo) * Carotenoid chroma (carotenoid chroma: S9 in pavo) - which quantifies the contribution of carotenoid pigments in the overall color. * Hue (nm) (H3: in pavo) - the principal color reflected by the feathers and measured as the wavelength at which reflectance is halfway between its minimum and maximum.  * Observer - indicates the individual who measured the reflectance spectra data. * Latitude - the geographic coordinate representing the north-south position of the sampling location, measured in decimal degrees. * Longitude - the geographic coordinate representing the east position of the sampling location, measured in decimal degrees * Elevation (m) - the height above sea level of the sampling location. **Note**: Missing information of museum where the specimens were deposited is replaced with 'null'. This information was not available on the specimen tags when the reflectance spectra was obtained. Climatic data including rainfall and temperature used in the analysis can be obtained from the WorldClim.org website.  ## Code/software Models and statistical tests were performed in R v.4.3.1