Cere colourimetry, annotator agreement and a chromatically ambiguous zone in the budgerigar (Melopsittacus undulatus): data and code

Annotations, colourimetric measurements, grouping keys, cere crops and the complete analysis code for the study "A chromatically ambiguous zone bounds visual sex determination in the budgerigar (Melopsittacus undulatus)". The archive reproduces every table and figure in the paper from the deposited material. The full-frame source photographs are not included; they belong to a public, openly licensed collection (Abdelmonsef 2023, CC BY 4.0), and manifest.csv names the source file behind each crop, so the exact subset can be reconstructed. See README.md for the layout and for how to reproduce each table and figure.