By Ilian Medarov, Class of 2028

Birds are some of the most colorful members of the animal kingdom, flaunting their colors to attract mates, communicate, and avoid predators. However, scientists are still figuring out how the different environments they evolved in brought about these colors over time. Researchers Jamie Dunning, Catherine Sheard, and John A. Endler decided to investigate this in a 2025 study that examined how light conditions, habitat, and the species’ migratory habits affected the evolution of their plumage coloration and contrast.

Dunning and colleagues, through a large avian spectral database,  pulled and analyzed color measurements from more than 2,600 bird species. They compared these data against behavioral and ecological data on habitat openness, migratory tendency, and the birds’ diel activity (night vs. day) of the birds. The researchers used visual models built around bird color perception, allowing them to estimate how contrasting feather colors appeared under different lighting conditions in the birds’ habitats. Because birds see differently than we do, especially in UV light, they used visual models based on what birds can see to show how birds perceive plumage under the previously stated conditions. Statistical models were then applied to compare recurring patterns across species while taking evolutionary history into account.

After applying the models, it was evident that visual conditions were strong predictors of plumage contrast, especially in females. For example, greater contrasts in color intensity and brightness were observed in the plumage of birds living in darker, denser habitats, allowing for greater visibility to potential partners in dim conditions. Aside from habitat, migratory species displayed different contrast patterns than their nonmigratory counterparts, indicating migratory behavior acts as an influencing factor. This is likely a result of a biological balance between communication and predator evasion, intended to maintain flock cohesion while still avoiding predation. On the other hand, diel activity showed no significant effect on coloration or contrast. This reveals how factors other than mating can still alter the development of bird plumage.

While plumage is most commonly linked with sexual selection, this study also shows how environmental visibility and ecological behavior play large roles in developing birds’ coloration. The differing colorations influenced by visibility and perception provide insight into the importance of ecological circumstances in animal communication. Future work on the subject could delve into effects on plumage from other factors, such as more general habitat structure, the variety and abundance of predators, and more unique behaviors.

Work’s Cited:

[1] Dunning, J., Sheard, C., & Endler, J. A. (2025). Viewing conditions predict evolutionary diversity in avian plumage colour. Proceedings of the Royal Society B: Biological Sciences, 292, 20241728. https://doi.org/10.1098/rspb.2024.1728

[2] Image retrieved from: https://commons.wikimedia.org/wiki/File:Carraca_lila_(Coracias_caudata),_parque_nacional_Kruger,_Sud%C3%A1frica,_2018-07-26,_DD_17.jpg