The Procellaria petrels represent a group of large and bulky seabirds that can be placed between the shearwaters of the genus Calonectris and the more fulmarine petrels. Until recently the largest of the Procellaria-species, the White-chinned and the only slightly smaller Spectacled Petrel, were considered to be conspecific. Now they are split into two separate species. Both have a large and strong bills, ivory colored with black sulci between the horny plates and ivory colored ungues, the latter sometimes slightly darker in the Spectacled Petrel. The Westland and Parkinson?s Petrel are also two similar species, of which the latter is a smaller version of the first. Both have ivory colored bills (with a bluish tinge in young birds), with blackish ungues. In the Parkinson’s the black is less extensive than in the Westland. There is no overlap in bill measurements. The Westland Petrel is of the same size as the White-chinned and its culmen is always longer than 47.8 mm. That of the Parkinson?s Petrel not longer than 45.1 mm The bill of the somewhat distinct Grey Petrel is about the size of the larger Procellarias, with the same pattern as the White-chinned and pectacled, but instead of ivory, more pearl-grey. The Grey Petrel’s somewhat lighter bill structure comes close to that of the Calonectris species. Because its somewhat different coloration, habits and structure this species formerly formed a genus of its own: Adamastor. It is now considered to belong to Procellaria.
Listen to the sound of Grey Petrel
Copyright remark: Most sounds derived from xeno-canto
|wingspan min.:||115||cm||wingspan max.:||130||cm|
|size min.:||48||cm||size max.:||50||cm|
|incubation min.:||52||days||incubation max.:||61||days|
|fledging min.:||110||days||fledging max.:||120||days|
Video Grey Petrel
copyright: Peter Fraser
In New Zealand waters, it is the most frequently killed species by the tuna-longline fishery (c.45,000 birds in total could have been caught in the last 20 years) and the selective mortality of adult females could be having an disproportionate impact on the breeding population. Substantial incidental mortality has also been recorded in fisheries off Australia, and it may be caught in significant numbers in international waters in the southern Indian Ocean, for which little seabird bycatch information exists. Any additional source of mortality that approaches 300 individuals was predicted to result in a population decline at the Kerguelen Islands, well below the strict minimum of 755 taken in the Patagonian fisheries operating around the islands. Introduced predators on the breeding islands are a further serious threat, for example, cats and black rat Rattus rattus on Crozet and Kerguelen, and, until their fairly recent eradication, cats on Marion Island. Brown rats Rattus norvegicus were eradicated from Campbell Island in 2001. The introduction of rats to Antipodes Island would be a major threat. Cats and Weka Gallirallus australis were probably responsible for extinction from Macquarie Island and brown rat and cats for its near extinction on Amsterdam. On Gough Island, recent evidence has indicated that introduced house mice Mus musculus are a significant predator of winter-breeding seabirds and are driving population declines of at least two species.