The rock shag, also known as the Magellanic cormorant, is a marine cormorant found around the southernmost coasts of South America. Its breeding range is from around Valdivia, Chile, south to Cape Horn and Tierra del Fuego, and north to Punta Tombo in Argentina. In winter it is seen further north, with individuals reaching as far as Santiago, Chile on the west coast and Uruguay on the east. The birds also breed around the coasts of the Falkland Islands.
Region
Southern South America and Falkland Islands
Typical Environment
Found along the southern Pacific and Atlantic coasts of South America from central Chile and Argentina south to Tierra del Fuego and Cape Horn, and around the Falkland Islands. Breeds on steep marine cliffs, offshore stacks, and rugged headlands exposed to strong currents. Forages almost exclusively in nearshore waters over rocky bottoms and kelp forests, rarely venturing far offshore. In the non-breeding season some individuals disperse northward along the coasts, sometimes reaching central Chile and Uruguay.
Altitude Range
Sea level to 200 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
Also called the Magellanic cormorant, the rock shag is a coastal seabird that nests on sheer sea cliffs and rocky ledges where surf and currents concentrate fish. It forages close to shore, often over kelp beds and tide rips, diving with strong underwater strokes. Adults show striking facial colors in the breeding season, including a blue orbital ring and orange-yellow facial skin. They usually breed in dense colonies and return to traditional sites year after year.
Rock shags nesting; Beagle Channel, Tierra del Fuego, Argentina
Temperament
social and colonial
Flight Pattern
low over water with rapid wingbeats
Social Behavior
Breeds colonially on narrow cliff ledges, often in dense groups. Pairs are largely monogamous within a season, with both sexes building the nest of seaweed and guano and sharing incubation and chick-rearing. Typical clutches are two to four eggs. Outside breeding, birds roost communally on rocks and ledges.
Migratory Pattern
Partial migrant
Song Description
Generally quiet at sea, but at colonies gives low, guttural grunts and croaks. Adults communicate with soft hisses and growls during pair interactions and at the nest.
