Stepfanie M Aguillon, Allison J. Shultz

Birds are known for their brilliant colors and extraordinary patterns. Sightings of individuals with atypical plumage often cause considerable excitement in the birding public, but receive little attention beyond reporting one-off sightings by the scientific community. In this perspective, we argue that sightings of individuals with atypical plumage submitted to community science platforms hold the potential to further our understanding of the evolution of plumage color and patterning in birds. As a demonstration, we outline two examples using sightings of leucistic individuals—those that lack melanin across the body or in certain feather patches. First, we discuss the potential for understanding carotenoid pigmentation with these sightings. Leucism influences melanins, but not carotenoids, and so the extent and distribution of carotenoids across the body are unmasked. In a leucistic individual, carotenoids may or may not be more extensive than what is typically visible and this could help to understand the energetic costs and constraints involved in obtaining, processing, and depositing carotenoids in different species. Second, we discuss how partial leucism could provide insights into plumage pattern evolution. We demonstrate that one can use the many observations present on community science platforms to identify repeated patterns in different partially leucistic individuals of the same species, and match these to patches present in related species. These patterns could be the result of shared underlying genetic variation that controls plumage patterning in birds over long evolutionary timescales. With these examples we outline a few potential lines of inquiry possible with atypical sightings submitted to community science platforms and note that other plumage aberrations provide additional opportunities. We encourage researchers to take full advantage of these chance sightings when they occur and database managers to make it possible to more easily tag photos of individuals with atypical plumage or other traits.