The Patagonian Crested Duck lives in pairs or groups which can be sometimes very large. This species frequents preferably the seashore and saline ponds but also freshwater rivers and streams; however, it is scarce or occasional in lakes, ponds and rivers in forested areas. It feeds by dabbling; its staple diet consists of insects and their larvae, crustaceans, small molluscs and algae. 

Wary and skittish, very territorial in breeding grounds, aggressively driving off intruders; nest is placed on the ground near the coast, hidden among shrubbery, up to six cream-coloured eggs are laid.