This is a bird of high elevations primarily in the central Andes. Note the puffy neck with raised feathers, typical of this newly recognized genus. It was formerly included as one of five (now four) Sheldgeese in the genus Chloephaga, but SACC accepted a 2014 proposal to move this species to Oressochen. A molecular study found it closer to the Orinoco Goose (Neochen jubatus) than either is to the Chloephaga clade. Now that Orinoco Goose and Andean Goose are considered congeners, the genus Oressochen Bannister, 1870 (type = melanopterus) has priority This change has been adopted by Clements/eBird but curiously not by IOC, HBW or HM4. Canon SX50 HS.
References:
Carboneras, C. & Kirwan, G.M. (2018). Andean Goose (Chloephaga melanoptera). 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/52828 on 17 April 2018).
Duvall, A. 2010. Andean Goose (Oressochen melanopterus), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.andgoo1.01
Remsen, J. V., Jr., J. I. Areta, C. D. Cadena, S. Claramunt, A. Jaramillo, J. F. Pacheco, J. Pérez-Emán, M. B. Robbins, F. G. Stiles, D. F. Stotz, and K. J. Zimmer. Version [17 April 2018]. A classification of the bird species of South America. American Ornithologists' Union. http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm