Data from: Inter- and intraindividual variation in the feather coloration of American crows
Data files
Feb 25, 2026 version files 50.16 KB
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CrowFeatherColoration_Data.xlsx
45.98 KB
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README.md
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Abstract
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.
Dataset DOI: 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
