Illustrations of handbook of the birds of the world: Datasets of RGB values and color classification of birds

Plumage color, an important trait of birds, has been widely studied from the perspectives of taxonomy, macroevolution, biogeography, and behavioral mechanisms. However, quantifying avian plumage color remains challenging, and data on the classification and proportion of plumage colors at the species or subspecies level are rarely reported. Some studies have examined plumage colors using illustrations from bird field guides, and hand-drawn illustrations have been shown to be an effective and rich resource for retrieving plumage data in large-scale ecological and biological studies. Here, we collected all illustrations from Handbook of the Birds of the World Alive (HBW Alive) and quantified them as RGB values. HBW Alive includes scientific illustrations of more than 10,000 species and subspecies on a uniform white background, which facilitates plumage quantification. We extracted RGB values from each image, excluding the white background, and applied the K-means clustering algorithm to ca..., , , # Illustrations of handbook of the birds of the world: Data sets of RGB values and color classification of bird

[https://doi.org/10.5061/dryad.70rxwdc6s](https://doi.org/10.5061/dryad.70rxwdc6s)

## Description of the data and file structure

We compiled two datasets comprising a total of 18,757 illustrations representing 10,290 species, including 5,288 subspecies (belonging to 2,746 species), 2,618 sexually dimorphic species, 456 species with multiple color morphs, and 231 species with different age classes (adult, juvenile, or immature). One dataset consists of the RGB data extracted from bird plates originally published in the *Handbook of the Birds of the World Alive* (HBW Alive) (del Hoyo et al. 2019), which helps future researchers to selectively choose and process raw data based on research needs. These electronic illustrations were downloaded in 2019, when they were still publicly available. Although *Handbook of the Birds of the World Alive* was later integrated into *Birds of...,