Data from: From colour to heat: Linking visible and near-infrared reflectance in birds using full-spectrum data
Data files
Jun 04, 2026 version files 10.29 MB
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code.zip
9.53 MB
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covariate_filter.csv
61.99 KB
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README.md
4.28 KB
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reflectance_averaged.csv
69.56 KB
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reflectence_body_region_measurement.csv
632.13 KB
Abstract
Feather reflectance in visible (VIS) and near-infrared (NIR) wavelengths governs avian heat balance by modulating the absorption of solar energy, yet the evolutionary and ecological patterns of NIR reflectance remain poorly understood. We developed a cross-taxonomic predictive framework linking NIR to VIS reflectance using a full-spectrum dataset of 531 bird species from 23 orders and 106 families, integrating 439 newly measured spectra with published data. Across species, VIS and NIR reflectance were strongly correlated (R² = 0.667), but regression slopes differed significantly among orders, indicating lineage-specific spectral scaling. When controlling for visible colouration, NIR reflectance still varied markedly across orders, revealing taxon-specific thermal properties beyond colour. Morphological and ecological traits further predicted these patterns, with Hand-Wing-Index, migratory status, habitat types, habitat temperature, and precipitation all exerting significant effects on NIR reflectance. Residual analysis revealed that Gruiformes, Pelecaniformes, and Charadriiformes, i.e, waders, gulls, terns, and allies, show low and variable NIR reflectance, possibly reflecting structural adaptations to heterogeneous thermal environments. Collectively, our results provide the first large-scale, phylogenetically informed framework for predicting NIR reflectance from VIS data, advancing mechanistic understanding of avian thermal adaptations.
Dataset DOI: 10.5061/dryad.v15dv429d
Description of the data and file structure
This dataset comprises the raw reflectance measurements of various body regions alongside composite reflectance data incorporating literature sources.
Files and variables
File: reflectence_body_region_measurement.csv
Description: Raw reflectance data for each body part of every specimen measured in SYSUM.
Variables
- number: specimen ID; unit: not applicable.
- sex: biological sex of specimen (male, female or NA); unit: not applicable.
- nape_NIR: near-infrared reflectance of the nape region; unit: % reflectance.
- nape_visible: visible reflectance of the nape region; unit: % reflectance.
- mantle_NIR: near-infrared reflectance of the mantle region; unit: % reflectance.
- mantle_visible: visible reflectance of the mantle region; unit: % reflectance.
- rump_NIR: near-infrared reflectance of the rump region; unit: % reflectance.
- rump_visible: visible reflectance of the rump region; unit: % reflectance.
- breast_NIR: near-infrared reflectance of the breast region; unit: % reflectance.
- breast_visible: visible reflectance of the breast region; unit: % reflectance.
- belly_NIR: near-infrared reflectance of the belly region; unit: % reflectance.
- belly_visible: visible reflectance of the belly region; unit: % reflectance.
- wing_NIR: near-infrared reflectance of the wing region; unit: % reflectance.
- wing_visible: visible reflectance of the wing region; unit: % reflectance.
- NIR_total: the average near-infrared reflectance of this specimen; unit: % reflectance.
- VIS_total: the average visible reflectance of this specimen; unit: % reflectance.
- species: scientific name; unit: not applicable.
- family: family of species; unit: not applicable.
- order: order of species; unit: not applicable.
- sexual: sexual dimorphism (1= yes or 0 = no ); unit: not applicable.
File: reflectance_averaged.csv
Description: The overall average reflectance for each species, incorporating both measured data and literature data.
Variables
- species_IUCNredlist: scientific names based on the IUCN Red List; unit: not applicable.
- species_birdtree: Scientific names based on the list in BirdTree; unit: not applicable.
- visible: average visible reflectance of species; unit: % reflectance.
- NIR: average near-infrared reflectance of species; unit: % reflectance.
- source: source of data (measurement, literatures or both); unit: not applicable.
- Order: order of species; unit: not applicable.
- Family: family of species; unit: not applicable.
- code_2024: 2024 IUCN Red List assessment of endangered status; unit: not applicable.
- notes: the specific source literature for the data has been annotated; unit: not applicable.
File: covariate_filter.csv
Description: Includes species information, reflectance data, morphological characteristics and ecological characteristics.
Variables
- Wing_Length: wing length (Tobias et al. 2022); unit: mm.
- Hand_Wing_Index:HWI, a dimensionless measure of wing shape calculated from the relative length of the hand-wing (Tobias et al. 2022); unit: dimensionless.
- Mass: body mass (Tobias et al. 2022); unit: g.
- Habitat: habitat type (Tobias et al. 2022); unit: not applicable.
- Habitat_Density: habitat density (Tobias et al. 2022); unit: not applicable.
- Migration: migration strategy (Tobias et al. 2022); unit: not applicable.
- visible: average visible reflectance of species; unit: % reflectance.
- NIR: average near-infrared reflectance of species; unit: % reflectance.
- Order: order of species; unit: not applicable.
- temperature: annual mean temperature within the species' habitat (Delhey et al. 2021); unit: °C.
- precipitation: annual mean precipitation within the species' habitat (Delhey et al. 2021); unit: mm/year.
- Species: scientific name; unit: not applicable.
File: code.zip
Description: The article contains statistical analysis code; detailed instructions are provided in the README file within the compressed archive.