Distribution in the Americas
Crested Ducks are endemic to South America; they comprise two subspecies that occupy different elevational environments in the Andes.
Lophonetta s. alticola occurs throughout the Andean highlands from northern Peru and Bolivia to central Argentina and Chile (2500-4800 masl). L. s. specularioides is found at low elevations (below 1500 masl) in the southern Andean regions of Patagonia (Argentina and Chile) and on the Falkland Islands.
The two subspecies intergrade in a zone of intermediate elevational habitats in Mendoza, Argentina, and Talca, Chile (Navas and Bo 1998, Bulgarella et al. 2007).
Crested Duck inhabits lakes, marshes and grassy areas, from shallow coastal bays and open marshes to high altitude lakes and lagoons, tarns, and bogs with small ponds, but it prefers larger lakes with barren shores. In the Altiplano, they gather in turbid, alkaline lakes with large concentrations of zooplankton (Fjeldså and Krabbe 1990). On the coast, they flock and feed in sheltered bays and on sea beaches, they also forage among the rocks and kelp beds (Johnsgard 1978). In the Falklands (Malvinas) Islands they are more often encountered on salt water, but also are found on ponds and creeks near the sea (Woods 1975).