Southern giant-petrel
Common name: Southern giant-petrel
Scientific name: Macronectes giganteus
Conservation status: The southern giant-petrel is 'Endangered' in Queensland (Nature Conservation Act 1992) and 'Endangered' nationally (Environment Protection and Biodiversity Conservation Act 1999).
Description: Southern giant-petrels can have a wing-span from 150-210cm. The dark morph of the species has a dark brown body with a white head and white mottling down the neck and leading edge of the wing. Its feet are fleshy-grey and bills are bulbous and tipped in pale green. The white morph has a similar bill but with white plumage and a few black spots on the body and wings.
Habitat and distribution: Southern giant-petrels range widely throughout the southern oceans. In summer they occur predominantly in sub-Antarctic to Antarctic waters, usually below 60°S in the South Pacific and south-east Indian Oceans, or 53°S in the Heard Island and Macquarie Island regions. Some adults are mainly sedentary, remaining close to their breeding islands throughout the year. Nonetheless, numbers diminish at all sites over winter - the Antarctic colonies being completely abandoned. Throughout the colder months, immature individuals and most adults disperse widely. The dispersal is circumpolar, extending north from 50°S to the Tropic of Capricorn and sometimes beyond. Thus, in winter they are rare in the southern waters of the Indian Ocean, and more common off South America, South Africa, Australia and New Zealand. The waters off south-east Australia may be particularly important wintering grounds. Most (84 percent) southern giant-petrels sighted off south-east Australia are immature birds.
Behaviour and life history: Southern giant-petrels nest annually in small colonies amongst open vegetation, with about 30 percent of the potential breeding population not attempting to breed each year. When successful, they raise a single chick. They feed on cephalopods ( e.g. squid, octopus, cuttlefish) and euphausiids (krill), attend fishing boats, scavenge on land, and prey on other birds on land or at sea. They are sensitive to human disturbance and will desert their nests if disturbed at the breeding colony.
Threatening processes: Longline fishing vessels operate throughout the range of the southern giant-petrel. When attempting to take bait from lines, giant-petrels are frequently caught and drowned on the baited hooks, with significant numbers being killed around breeding islands. On Macquarie Island, breeding success and/or nest-site selection have probably been adversely affected by predation by rats, cats and an elevated number of Subantarctic skuas Catharacta lonnbergi, although the threat from the latter two has been substantially reduced. Construction of three research bases in the Australian Antarctic Territory has probably caused localised reductions in the number of breeding southern giant-petrels. Ingestion of plastics and hooks, and their regurgitation to chicks, entanglement in marine debris, human disturbance and accumulation of chemical contaminants may also pose risks to this species. Decreases and extirpations recorded throughout the breeding range indicate present mortality rates cannot be sustained.
Recovery actions:
- A Threat Abatement Plan (TAP) to minimise fishing bycatch has been prepared and effective mitigation techniques have been developed and are being improved.
- Bycatch rates in the Australian Fishing Zone and the success of mitigation measures have to be monitored and the results quickly analysed .
- Measures known to be effective in mitigating seabird bycatch within the Australian Fishing Zone are promoted in programs directed towards fishing operators.
- Tourists on breeding islands have to be managed to prevent disturbance.
- Continued monitoring of breeding population size and success will determine any population fluctuations.
Further information:
Environment Australia. 2001. Recovery Plan for Albatrosses and Giant-petrels. Environment Australia, Canberra.
Last updated: 22 August 2006