A tiny, puffin-like bird that flies low and fast over the water with whirring wingbeats, the South Georgia diving-petrel (Pelecanoides georgicus) is a stocky, short-necked seabird with small legs (3)(4). The stubby, hooked bill has a short nasal tube with upward-facing nostrils, and the small, paddle-like wings are adapted for underwater propulsion (5)(6). The South Georgia diving-petrel has typical diving-petrel plumage, with black upperparts and dull white underparts, and it is virtually indistinguishable from the common diving-petrel (Pelecanoides urinatrix) (3)(7).
Also known as
Georgean diving petrel, Georgian diving petrel, Georgian diving-petrel, South Georgia diving petrel, South Georgian diving petrel, South Georgian diving-petrel.
Unlike many other petrels, the South Georgia diving-petrel does not stray far from its nesting islands, even outside of the breeding season (2)(5). It is highly adapted to swimming, and catches its fish or crustacean prey after a short underwater pursuit. Its flight often appears heavy, and when confronted by a high wave, it flies straight through the wave rather than over it. This species is also more heavily boned than land birds, which helps to combat its natural buoyancy. When foraging, it dives headlong into water, expelling air from its lungs and compressing its plumage by muscle contraction. Most dives last less than a minute, and captured prey is carried back to the nest in a throat pouch (3).
The South Georgia diving-petrel breeds from October to February each year. It nests in burrows that are around 80 centimetres long, with a nest chamber at the end (2). It is nocturnal around the colonies to avoid predation by gulls and skuas. The South Georgia diving-petrel calls at night from inside the burrow to attract a mate, but as these calls have the undesirable side-effect of attracting predators, the South Georgia diving-petrel also produces a background noise that scrambles its calls and makes it difficult for predators to locate the bird (5). A single egg is laid, and is incubated for 44 to 52 days. The chick is brooded for six days and then fed at night by both adults (2). The South Georgia diving-petrel is thought to breed for the first time in its second year (3).
A widespread species in the Southern Ocean, the South Georgia diving-petrel breeds on scattered oceanic volcanic islands in the sub-Antarctic region, from South Georgia in the south Atlantic and the Prince Edward Islands off South Africa, through Crozet, Kerguelen and Heard Islands in the southern Indian Ocean, to Codfish Island off New Zealand (3)(8).
Outside of the breeding season, the South Georgia diving-petrel is typically found offshore over cool, deep waters. It uses coastal habitats whilst breeding, when it nests in burrows in cooled lava or under sand dunes on relatively flat land (5)(8).
A widespread species with an extremely large population, estimated at over 15 million individuals in 2004 (9), the South Georgia diving-petrel is not currently considered at risk of extinction. However, its populations are in decline as a result of predation by introduced mammals and habitat degradation (8).
Brown rats (Rattus norvegicus) were introduced to South Georgia by sealers and whalers in the early 1800s and remain one of the greatest threats to its wildlife, predating ground-nesting birds and their eggs and chicks (10)(11). It is likely that predation by brown rats has seriously affected this species on South Georgia. Furthermore, the South Georgia diving-petrel became extinct on Marion Island as a result of predation by introduced cats. It is also extinct on the Auckland Islands, due to habitat loss caused by the large Hooker’s sea lion (Phocarctos hookeri) population, which has destroyed the South Georgia diving-petrel’s burrows (2)(3)(7).
The South Georgia diving-petrel has not been the target of any known specific conservation measures. However, a high priority for conservation on South Georgia is to eradicate rats from the island. The South Georgia Heritage Trust is planning an eradication programme to start in 2011, as part of a Habitat Restoration Project to remove rats and restore the island to its status as one of the most important seabird islands in the world. Precautions are also being taken to prevent rats from reaching offshore islands, although the remote location makes this difficult to regulate in practice (10)(11).
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Diverse group of animals with jointed limbs and a hard chitinous exoskeleton characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.
To keep eggs warm so that development is possible.
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