Torrent Duck

Merganetta armata

Surfs Andean whitewater rapids with stiff tail and streamlined body. Lives where most birds would drown.

Population: ~20,000–35,200 individuals total (13,300–23,500 mature individuals); population trend decreasing, with documented declines in NW Patagonia (Argentina) and suspected declines in Venezuela (BirdLife International, 2025 assessment; underlying count data partly dated to 1997)
Habitat: Fast-flowing, clear mountain rivers, streams, and torrents in the Andes — rapids, boulder-strewn gorges, and waterfalls, plus calmer stretches — from near sea level (in Chile) up to roughly 4,500–4,900 m elevation (Animal Diversity Web gives 300–4,600 m)
Fun fact: The Torrent Duck is the sole member of its genus, Merganetta, and is a whitewater specialist that swims and dives through raging Andean rapids — even foraging behind waterfalls — yet is reluctant to fly more than short distances.
Range: The Andes of western South America across seven countries — Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina — in six subspecies (three widely accepted: colombiana, leucogenis, armata; three disputed: berlepschi, garleppi, turneri), from the Santa Marta range of Colombia/Venezuela south to Tierra del Fuego
Diet: Aquatic invertebrates — stonefly, mayfly, and caddisfly larvae, other insect larvae, molluscs, and crustaceans — with occasional small fish and terrestrial worms; competition from introduced trout reduces prey availability in some rivers
Size: 0.445 m
Lifespan: 18 years

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