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Three of the 6 widely accepted species of Pachyptila were first described and named on the basis of specimens collected between 1768 and 1780 during James Cook’s 3 voyages of circumnavigation. Two of them, the thin-billed prion Pachyptila belcheri (Mathews, 1912) and the broad-billed prion Pachyptila vittata (Forster, 1777), were described and named on the 1st voyage as Procellaria turtur and Procellaria latirostris respectively, but those descriptions and names were never published at the time. As a result, the specific name which had been applied to 1 of them – turtur – became attached to a different taxon, the fairy prion Pachyptila turtur (Kuhl, 1820). The description of Procellaria vittata by Reinhold Forster, and the painting of it by his son, which were based on specimens taken in the southern Indian Ocean during the 2nd voyage, actually relate to the Antarctic prion Pachyptila desolata (Gmelin,1789), and not to the broad-billed prion as previously believed. It would therefore be inappropriate to designate the bird in George Forster’s painting of an Antarctic prion as the type of the broad-billed prion as has been suggested. The correct type locality of Pachyptila vittata Forster, 1777 is 56°11ʹ, 31°9ʹE. Latham’s description of the “Broad-billed Petrel”, and therefore Gmelin’s Procellaria vittata of 1789, is shown to have been based primarily on a specimen of the broad-billed prion. The type locality of Pachyptila vittata Gmelin, 1789 is not known. Latham’s description of the “Brown-banded Petrel”, and therefore Gmelin’s Procellaria desolata of 1789, was based on a 3rd voyage Pachyptila specimen from Kerguelen Island. However, Latham’s description could apply to any 1 of the 3 species of Pachyptila which breed at that locality.

The importance of fisheries waste in the diet of Westland petrels (Procellaria westlandica) was assessed using 3 different techniques. Dietary studies showed that during the hoki (Macruronus novaezelandiae) fishing season (mid June – early September), fish waste formed c. 63% of the solid food brought back to the colony and fed to chicks. After the hoki season, fisheries waste contributed only c. 25% to the diet. A survey of Westland petrels at sea found that, although vessels fishing for hoki influence the petrels’ distribution, only a small proportion of the population appears to use this food resource at any one time. Satellite tracking showed that, on average, birds spent 1/3rd of each foraging trip near vessels, but they foraged over much wider areas than those occupied by the fishing fleets. Although fishery waste now forms a substantial component of the Westland petrel’s diet, the situation suggests opportunistic use of a readily available resource, rather than dependence.