Heard Shag
Encyclopedia
The Heard Island Shag or Heard Island Cormorant, is a marine cormorant
native to the Australia
n territory comprising the Heard and McDonald Islands
in the Southern Ocean
, about 4100 km south-west of Perth
, Western Australia
.
s, sometimes placed in the genus
Leucocarbo, and a subspecies
of the Imperial Shag
. It is sometimes considered to be a full species.
Heard and McDonald Island
s, and is only known to breed on Heard Island. Apart from breeding and roosting, its habitat
is marine.
s above the base of the bill
in front of the eyes as well as blue eye-rings. It is about 77 cm in length, with a wingspan
of 120 cm and a weight of 3 kg.
s and adhering soil of the tussock grass Poa cookie and average about 22 cm high, with a minimum distance between nests of 50 cm. The clutch of 2-3 eggs is laid mainly between mid September to November, hatching from November to February. The chicks fledge from January to March.
. The proportion of fish in the diet is higher when the birds are feeding chicks.
under Australia's Environment Protection and Biodiversity Conservation Act 1999
, because the population is small, localised and subject to fluctuations in breeding success due to weather conditions and food availability. A potential threat is climate change
affecting sea temperatures and thus food supply.
Cormorant
The bird family Phalacrocoracidae is represented by some 40 species of cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed.- Names :...
native to the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n territory comprising the Heard and McDonald Islands
Heard Island and McDonald Islands
The Heard Island and McDonald Islands are an Australian external territory and volcanic group of barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall size is in area and it has of coastline...
in the Southern Ocean
Southern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...
, about 4100 km south-west of Perth
Perth, Western Australia
Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....
, Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
.
Taxonomy
The Heard Island Shag is one of the blue-eyed shagBlue-eyed shag
The blue-eyed shags are a group of closely related cormorant taxa. All have a blue, purple or red ring around the eye ; other shared features are white underparts and pink feet....
s, sometimes placed in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Leucocarbo, and a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the Imperial Shag
Imperial Shag
The Imperial Shag, Phalacrocorax atriceps, is a black and white cormorant native to many subantarctic islands, the Antarctic Peninsula and southern South America, primarily in rocky coastal regions, but locally also at large inland lakes. It is sometimes placed in the genus Leucocarbo instead...
. It is sometimes considered to be a full species.
Distribution and habitat
The Heard Island Shag is restricted to the subantarcticSubantarctic
The Subantarctic is a region in the southern hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° – 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Indian Ocean, Atlantic Ocean and...
Heard and McDonald Island
McDonald Island
McDonald Island may refer to*Heard Island and McDonald Islands, in the Southern Ocean, administered by Australia.*McDonald Island , in Frederick Sound near Petersburg.*McDonald Island , in San Joaquin County on the San Joaquin River....
s, and is only known to breed on Heard Island. Apart from breeding and roosting, its habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
is marine.
Description
The Heard Island Shag has largely black upperparts and white underparts. The cheeks and ear-coverts are white; there are white bars on the wings, a black, recurved crest over the forehead, and pink feet. A breeding adult has a pair of orange caruncleCaruncle
Caruncle may refer to:*In botany, an elaiosome , especially in the plant family Euphorbiaceae*In animal anatomy:**prostomium, the sensory organ of Annelid worms...
s above the base of the bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
in front of the eyes as well as blue eye-rings. It is about 77 cm in length, with a wingspan
Wingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
of 120 cm and a weight of 3 kg.
Behaviour
Heard Island Shags are gregarious, roosting in groups of from 10-20 birds up to several hundred.Breeding
The birds are present all year round at Heard Island, where they breed annually in colonies. Courtship takes place from late August to early October. Nests are mounds built largely of the stipes, rootRoot
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
s and adhering soil of the tussock grass Poa cookie and average about 22 cm high, with a minimum distance between nests of 50 cm. The clutch of 2-3 eggs is laid mainly between mid September to November, hatching from November to February. The chicks fledge from January to March.
Feeding
The birds forage locally in shallow coastal waters, with the diet consisting primarily of polychaetes and fishFish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
. The proportion of fish in the diet is higher when the birds are feeding chicks.
Status and conservation
The Heard Island Shag population is estimated to comprise about 1000 breeding pairs. It is listed as vulnerableVulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
under Australia's Environment Protection and Biodiversity Conservation Act 1999
Environment Protection and Biodiversity Conservation Act 1999
The Environment Protection and Biodiversity Conservation Act 1999 is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and culturally significant places...
, because the population is small, localised and subject to fluctuations in breeding success due to weather conditions and food availability. A potential threat is climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
affecting sea temperatures and thus food supply.