This is the largest and most common of the three species of coots in the area. It is easily identified by its yellow bill separated from the pointed frontal shield by a red spot. Red-gartered Coots range in fresh water throughout southern South America. Most coots feed on aquatic vegetation as seen here, but in some areas this species specializes on small grapsid crabs (Cyrtograpsus angulatus). Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope III | 30XWA | hand-held (no adapter).
References:
Red-gartered Coot (Fulica armillata), In Neotropical Birds Online (, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. retrieved from Neotropical Birds Online: https://neotropical.birds.cornell.edu/Species-Account/nb/species/regcoo1
Taylor, B. (2018). Red-gartered Coot (Fulica armillata). 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/53701 on 22 April 2018).