|Photo by Nick Athanas (Antpitta)
This species breeds along the coasts of southern South America, in Tierra del Fuego and the Falkland Islands. During winter they range north as far as the coasts of Uruguay and the coast of Chile as far north as Valparaíso.
These birds are 66-71 cm long and have a wingspan of 92 cm. They weigh up to 1,5 kg.
Rock shags forage in coastal water, particularly in kelp beds, favouring areas along rocky coastlines in channels and sheltered bays, and also in harbours, estuaries and inland waters. They typically nests on cliff ledges and on top of steep-sided rocks or islets, as well as in gulleys, caverns and occasionally on exposed shipwrecks and jetties.
They forage by pursuit diving, taking small benthic fish, crustaceans, cephalopods and polychaetes.
The rock shag breeds in October-February. They nest in small colonies, which are often occupied throughout the year. Each pair builds a cup-shaped nest from seaweed, tussock grass and leaves, which are cemented together by mud and guano. The female lays 2-5 eggs which are incubated by both parents but there is no information regarding the leght of the incubation period. Chicks are fed by both parent, often even after fledging, but there is no information regarding the length of the fledging period.
IUCN status – LC (Least Concern)
This species has a large breeding range and is described as locally common, but not abundant. The population in the Falkland islands has been estimated at 60.000 breeding pairs. Although this species is not threatened at present, increasing levels of pollution by oil and rubbish together with expanding ecotourism industries bringing rising numbers of tourists to seabird colonies by pose some impacts in the future.