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Dryad

Viewing conditions predict avian plumage contrast

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Mar 14, 2025 version files 1.87 MB

Abstract

Birds communicate using multiple sensory channels, most commonly through vocalisations and colourful plumage patches. Such colourful plumage has evolved through a complex interplay of processes, acting not only on the ability of a patch to convey information but also in response to physiological and environmental factors. Although much research on inter-specific variation in bird plumage has concentrated on sexual selection, much less work has considered the role of non-sexual selection and how it is affected by joint effects of avian viewing conditions and receiver vision. Here we combined taxonomically diverse databases of avian plumage measurements with habitat use and behavioural data to test the effect of three factors which effect viewing conditions - habitat openness, migratory preference, and daily phenology - on avian plumage contrast, accounting for shared evolutionary history and variation in avian visual systems. We find that habitat structure and migratory preference predicted plumage visual contrast, especially for females. Our study demonstrates the important role of non-sexually selected traits and viewing conditions in shaping avian plumage contrast.