A case of melanism in a Gentoo Penguin (Pygoscelis papua) at Esperanza/Hope Bay, Antarctica

Abstract

Gentoo Penguin (Pygoscelis papua) is a species that reproduces in Antarctica and sub-Antarctic islands. During 2022 a Gentoo Penguin with an unusual plumage coloration was recorded at Esperanza/Hope Bay, north of the Antarctic Peninsula (63°24′ S, 57°01′ W). The coloring of plumage is achieved by two types of pigments known as carotenoids and melanins. Two different types of melanin (phaeomelanin and eumelanin) are responsible of producing different pigmentation patterns that oscillates between reddish-blackish coloration. The unusual coloration of the penguin was identified as melanism, a genetic condition that causes an excess of melanin pigment in feathers. This particular individual appeared to be in good health and exhibited normal behavior. As far as we know this is the second official report of melanism for the species since the first one in 1997 and it is the first report for the colony.