DOI: 10.5061/dryad.stqjq2chg
title: Data from: Inter- and intraindividual variation in the feather coloration of American crows

description: Avian feathers are remarkably diverse in both form and function.
 Coloration is among the most studied features of feathers, but we know
 relatively little about melanin-based black coloration. Despite many crows
 (Corvus sp.) and other corvids having black feathers that appear uniform
 to human perception, their feather coloration could play an important role
 in social communication. We therefore tested whether the
 coloration of American crow (Corvus brachyrhynchos) feathers varied by age
 class and sex, two socially-relevant variables. Using a visual modeling
 approach that accounts for the visual system of American crows, we
 measured the coloration of American crow feathers from museum specimens.
 We found that feather coloration varied by age class but not sex. Older
 individuals had feathers with a different hue and more ultraviolet than
 younger crows. Discriminant function analyses correctly categorized
 individuals into age classes based on feather coloration with high
 classification success. The coloration of American crow feathers did not
 vary based on the time since the last molt and replacement, but did vary
 with the time since the specimen was collected. The visual modelling
 approach suggests that crows can discriminate among different feather
 regions. One region with particularly distinctive coloration properties
 was a facial mask, which could potentially function to minimize eye glare.
 Our results suggest that feather coloration in American crows (and
 potentially other seemingly monomorphic corvids) could reflect underlying
 qualities of those individuals that are important for social
 communication. Associated data in the manuscript is provided.
description: # Data from: Inter- and intraindividual variation in the feather
 coloration of American crows Dataset DOI:
 [10.5061/dryad.stqjq2chg](https://doi.org/10.5061/dryad.stqjq2chg) ##
 Description of the data and file structure The data were collected from
 museum specimens of American crows at the Texas A&M University
 Biodiversity Research and Teaching Collections. Empty cells represent data
 not available. ### Files and variables #### File:
 CrowFeatherColoration_Data.xlsx **Description:** FeatherColoration #####
 Variables * MuseumCatalogNumber: The museum catalog number of the
 specimen. * Sex: The sex of the specimen. 'M' for males and
 'F' for females. If the sex of the specimen was unknown, it is
 empty.  * AgeClass: Categorized into four categories (1-4). Category 1 was
 juveniles through their first birthday up to their first full molt,
 category 2 was immature, but independent birds, category 3 was young but
 reproductively mature birds (2-year-olds), and category 4 was
 reproductively mature birds of three or more years that could have been
 breeders. * TimeSinceLastMolt_Months: Ranged from 0 to 13 months. For
 birds in age class category 2-4, this variable ranged from 0 months
 (indicating that the bird molted in the same month as their death) to 12
 months (indicating that the bird molted 12 months before their death). For
 birds in age class category 1, this variable could also extend beyond 12
 months because yearlings only molt body feathers, not flight feathers, in
 their previous (first) August as juveniles. * StorageDuration_Yr: The date
 the specimens were photographed minus the date they were salvaged, in
 years. If the date the specimens were salvaged was unknown, it is empty. 
 * WingLength_mm: Straight-line distance between the angle of the wrist
 joint and the tip of the longest primary feather in mm. * ROI: Regions of
 interest within images of the specimens that defined specific feather
 patches, including DB (dorsal body, tail, and wings), DH (dorsal head and
 neck), DF (dorsal forehead), VT (ventral tail), VB (ventral body), VN
 (ventral throat and neck), VC (ventral chin), LW (lateral wing), LT
 (lateral top of eye), LS (lateral side of eye), and LU (lateral under
 eye). * HueVIS: Tetracolorspace values of hue theta. If it was not
 possible to calculate this value (i.e., the feathers were missing within
 the ROI), it is empty.  * HueUV: Tetracolorspace values of hue phi. If it
 was not possible to calculate this value (i.e., the feathers were missing
 within the ROI), it is empty.  * Saturation: Tetracolorspace values of
 achieved chroma. If it was not possible to calculate this value (i.e., the
 feathers were missing within the ROI), it is empty.  * Luminance:
 Reflectance across all wavelengths. If it was not possible to calculate
 this value (i.e., the feathers were missing within the ROI), it is empty. 
 * Glossiness: Quality of mirror-like or specular reflectance. Larger
 values indicate feathers that are glossier. If it was not possible to
 calculate this value (i.e., the feathers were missing within the ROI), it
 is empty.  * State: State in which the specimen was collected (Oklahoma,
 Washington, or Texas). **Description:** Summary ##### Variables *
 MuseumCatalogNumber: The museum catalog number of the specimen. * Sex: The
 sex of the specimen. 'M' for males and 'F' for
 females. If the sex of the specimen was unknown, it is empty.  *
 WingLength_mm: Straight-line distance between the angle of the wrist joint
 and the tip of the longest primary feather in mm. * AgeClass: Categorized
 into four categories (1-4). Category 1 was juveniles through their first
 birthday up to their first full molt, category 2 was immature, but
 independent birds, category 3 was young but reproductively mature birds
 (2-year-olds), and category 4 was reproductively mature birds of three or
 more years that could have been breeders. * State: State in which the
 specimen was collected (Oklahoma, Washington, or Texas). ## Code/software
 Microsoft Excel can be used to view the data ## Access information Other
 publicly accessible locations of the data: * None Data was derived from
 the following sources: * None