A brown Adélie Penguin Pygoscelis adeliae breeding at King George Island, Maritime Antarctica

Plumage aberrations are rare in penguin species. Tracking their occurrence is helpful to understand the effects of these phenotypes on the life history of penguins, especially on mating, breeding, and foraging success. We registered a brown Adélie Penguin Pygoscelis adeliae at Turret Point, King George Island, Maritime Antarctica, during the middle of the 2017/2018 breeding season. The individual was brooding one chick in a nest located in the center of the colony and its partner was by its side. Both chick and partner showed normal plumage, reaffirming the recessive character of brown mutations. A breeding aberrant bird nesting in the center of the colony indicates that the brown coloration does not seem to affect mate selection, but we could not verify if it affects breeding success. This is the third published record for Adélie Penguins following a gap of 40 years. We stress, however, that possible misclassifications of brown aberrations in literature might be causing an underestimation of its occurrence rate in bird populations.