The remaining sea birds and waders are a curious and unlikely mix. Brackish lagoons and ponds support small populations of white-cheeked pin-tailed ducks and American flamingos. The cooler waters on the western side of the archipelago, and selected sites in the center, such as Bartolome, support populations of the endemic Galapagos penguin. This penguin, the smallest in the world, is the only one to live on the equator, where the warm equatorial waters are cooled by the cold Humboldt current.