Britannica
Sources used in this answer
Why do black-billed birds that hunt in bright sunlight have less glare near their eyes?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
coloration
The anole changes color in response to its stress level.
Birds that forage for aerial insects in bright sunlight often possess black bills because the dark coloration reduces light reflectance near the eyes. In brightly lit environments, excessive reflected light can create blinding glare or dazzle, which diminishes visual contrast and interferes with the visually demanding task of hunting insects. By absorbing light rather than reflecting it, the black bill helps maintain optimal visual clarity for the bird.1