Ranging through Southern South America, this is the world's largest grebe. The population in coastal Peru is geographically isolated and it has been suggested that it may constitute an undescribed race. The streaking and mottling on its face indicate juvenal plumage.
Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope III | 30XWA | hand-held (no adapter).
References:
Fjeldså, J. (2004) The Grebes. Oxford University Press, Oxford & New York.
Great Grebe (Podiceps major), In Neotropical Birds Online (T. S.Schulenberg, editor). Cornell Lab of Ornithology, Ithaca, New York, USA. retrieved from Neotropical Birds Online: https://neotropical.birds.cornell.edu/Species-Account/nb/species/gregre1
Llimona, F., del Hoyo, J., Jutglar, F. & Kirwan, G.M. (2018). Great Grebe (Podiceps major). 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/52487 on 12 January 2018).