Imperial Shag

The Imperial Shag, or Imperial Cormorant (Leucocarbo atriceps), presents a striking figure with its glossy black plumage contrasted by a white belly and neck. This seabird is further adorned with a distinctive blue ring around its eyes, an orange-yellow nasal knob, and pinkish legs and feet. During the breeding season, it sports an erectile black crest, which is absent or reduced outside this period.

Identification Tips

Adult Imperial Shags measure between 70–79 cm in length and weigh 1.8–3.5 kg, with males typically larger than females. Their serrated bill is adept at catching fish. In non-breeding plumage, adults have a less vibrant facial area and may show less white on their back and wings. Juveniles and immatures are brownish with white, lacking the bright facial skin and nasal knob of adults.

Habitat

These birds are native to southern South America, favoring rocky coastal regions and occasionally found at large inland lakes.

Distribution

The Imperial Shag is found along the coasts of southern Chile and Argentina. It is also present in the Falkland Islands and various subantarctic islands, including the South Georgia and South Sandwich Islands, South Orkney Islands, Heard Island, and the Crozet and Prince Edward Islands.

Behaviour

Imperial Shags are colonial and monogamous, nesting in small to large colonies that may include hundreds of pairs. These colonies are often shared with other seabirds such as rock shags, southern rockhopper penguins, and black-browed albatrosses.

Breeding

Nests are constructed from seaweed and grass, bound together with mud and excrement. Clutches typically consist of two to three eggs, which are incubated by both parents for about five weeks. Predation by skuas and sheathbills is a significant threat to eggs and chicks.

Diet and Feeding

Their diet includes small benthic fish, crustaceans, polychaetes, gastropods, and octopuses, with a preference for Argentine anchoita. Imperial Shags are known to dive to nearly 25 m on average, and have been recorded diving as deep as 60 m to forage on the sea floor. They generally feed inshore, though some populations venture further out to sea.

Conservation status

The Imperial Shag is currently listed as Least Concern by BirdLife International and the IUCN. Most subspecies are relatively common, with population estimates exceeding 10,000 pairs for each.

Similar Species

Variations within the species are primarily in the amount of white on the cheeks, ear-coverts, wing-coverts, and back. The white-cheeked and black-cheeked morphs can be found in some populations, and hybrids between the two have been observed.