plumage coloration

sexual dichromatism

The Wilson Journal of Ornithology

We examined the fluorescence of ornaments among three auklet species: Least Auklets (Aethia pusilla), Crested Auklets (Aethia cristatella), and Parakeet Auklets (Aethia psittacula) on Gareloi Island, Alaska during the 2015 breeding season. We found that the ornamental bill plates of Crested Auklets fluoresced, but bill ornaments of Least Auklets and bills of Parakeet Auklets did not. We also found that none of the feathers in these three species exhibited fluorescence. We suggest that differences in ornamentation and fluorescence may be related to life-history strategies associated with sexual selection and predator avoidance.

Glowing in the light: fluorescence of bill plates in the Crested Auklet (Aethia cristatella)