The Heard Island shag, or Heard Island cormorant, is a marine cormorant native to the Australian territory comprising the Heard and McDonald Islands in the Southern Ocean, which is about 4,100 km south-west of Perth, Western Australia.
Region
Subantarctic Indian Ocean
Typical Environment
This species is confined to coastal waters and shorelines around Heard Island and McDonald Islands. It frequents rocky coasts, kelp beds, and nearshore shelf waters where upwelling and currents concentrate prey. Breeding occurs on sea cliffs, rock stacks, and slopes with access to the ocean. Birds typically forage within a short radius of colonies and seldom disperse far from the archipelago.
Altitude Range
Sea level to 150 m
Climate Zone
Polar
Ease of Keeping
Beginner friendly: 1/5
The Heard Island shag, also called the Heard Island cormorant, is a blue‑eyed shag restricted to the remote Australian territory of Heard and McDonald Islands in the Southern Ocean. It breeds in small cliff‑side colonies and forages close to shore, diving for fish and invertebrates in frigid subantarctic waters. Its isolation offers some protection from predators, but its tiny range makes it vulnerable to environmental change and severe weather.
Temperament
colonial and alert
Flight Pattern
strong flier with rapid wingbeats, usually low over the water
Social Behavior
Breeds in small to medium colonies on cliffs and rocky ledges, constructing nests of seaweed, grass, and guano. Pairs are likely monogamous within a season, with both sexes incubating and feeding chicks. Adults return to favored colony sites annually when conditions allow.
Migratory Pattern
Resident
Song Description
Generally quiet at sea, but at colonies emits low guttural croaks, grunts, and hisses. Vocalizations are most frequent during pair bonding, nest defense, and chick provisioning.
Plumage
Glossy black upperparts with clean white underparts; black head and neck with a subtle greenish sheen. In breeding condition, facial skin shows vivid caruncles and a bright blue orbital ring.
Diet
Primarily a pursuit diver taking benthic and pelagic fish, along with cephalopods and crustaceans. It uses powerful feet and partially spread wings to propel underwater, often diving to considerable depths in nearshore waters. Prey is swallowed underwater or brought to the surface; adults regurgitate partially digested food for chicks.
Preferred Environment
Forages in kelp beds, rocky inshore zones, and along the island shelf where currents concentrate prey. Most feeding occurs within a few kilometers of breeding sites and in relatively sheltered lee shores.
