These peculiar chicken-like birds make a living in penguin colonies by stealing regurgitated krill from adult penguins. Otherwise they are scavangers and we observed them feeding primarily on penguin feces. Adults (top) are all white. Immatures (bottom) are freckled and have reduced facial caruncles and bill sheath. Sheathbills are classified in there own family Chionidae, the only bird family endemic to the Antarctic and sub-Antarctic regions. Canon PowerShot SX50 HS
References:
Burger, A.E. & Kirwan, G.M. (2018). Snowy Sheathbill (Chionis albus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/53952 on 7 June 2018).
Fang, E. D. (2010). Snowy Sheathbill (Chionis albus), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.snoshe2.01