[order] PROCELLARIIFORMES | [family] Hydrobatidae | [latin] Garrodia nereis | [authority] Gould, 1841 | [UK] Grey-backed Storm-petrel | [FR] Oceanite nereide | [DE] Graurucken-Sturmschwalbe | [ES] Paino Dorsigris | [NL] Grijsrugstormvogeltje
Subspecies
Monotypic species
Genus
Storm-petrels are rather small and often dark colored tubenoses with a world wide distribution. All have fine black bills with very pronounced tubes. Storm Petrels are separated in two groups: the long legged, Southern Hemisphere birds subfamily Oceanitinae and the shorter legged species of more northern seas the subfamily Hydrobatinae. The first groups shows more morphological differences than the second. The genera are characterised on colour patterns, the condition of the nasal tubes, tail shape, structure of claws and proportions of the leg bones. The genus Garrodia have their plumage grey on black, white below; bill short, nasal tubes about half length of culmen and upturned at end; tarsus scutellate in fornt, claws slightly flattened, webs black.
Physical charateristics
Head, neck, and all the upper surface dark ash-grey; rump and upper tail-coverts paler, or silvery grey; under surface pure white, the grey plumage presenting a distinct margin across the upper part of the breast. Irides and bill black, the latter whitish towards the base of lower mandible; legs and feet dark brown.
| wingspan min.: | 38 | cm | wingspan max.: | 40 | cm |
| size min.: | 16 | cm | size max.: | 19 | cm |
| incubation min.: | 44 | days | incubation max.: | 46 | days |
| fledging min.: | 0 | days | fledging max.: | 0 | days |
| broods: | 1 | eggs min.: | 1 | ||
| eggs max.: | 1 |
Range
Southern Ocean : widespread. The Grey-backed Storm-petrel has a circumpolar distribution in the subantarctic, breeding on islands from the Falkland Islands (Islas Malvinas) in the south-west Atlantic east to the Chatham Islands (New Zealand). Individuals can winter nearer to the continents, being found off the extreme southern coast of Argentina, and south-east Australia and Tasmania
Habitat
This marine species occurs in the cool waters of the subantarctic zone. It is generally found over the edge of the continental shelf and is apparently only pelagic during dispersal
Reproduction
Its breeding season starts in October or November, with individuals forming loose colonies on oceanic islands, creating burrows in vegetation or nesting in crevices in rocks. The female laying a single egg in November or December which is incubated by both parents for about 45 days. The chick fledges after about 90 days in April or May.
Feeding habits
Its diet comprises mainly of immature barnacles and other crustaceans, but also small squid and occasionally small fish. It catches prey mostly by pattering over the sufrace whilst in flight, but also by dipping and shallow plunging. It has been seen to attend trawlers and occasionally follows ships.
Conservation
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Migration
In most cases probably disperses only to waters adjacent to colony, but little known. Birds from Crozet Is absent in winter; species occurs regularly off SE Australia and Tasmania.
Distribution map
