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 Westland Petrel
Copyright remark: Most sounds derived from xeno-canto
|wingspan min.:||135||cm||wingspan max.:||140||cm|
|size min.:||50||cm||size max.:||55||cm|
|incubation min.:||57||days||incubation max.:||65||days|
|fledging min.:||120||days||fledging max.:||140||days|
Video Westland Petrel
copyright: Brooke Clibbon
Introduced mammals and the native Weka Gallirallus australis prey on eggs, chicks and adults, goats trample burrows, and contribute to the erosion of subcolonies. Mining and agriculture may have destroyed some available habitat but this has probably had little impact on the population as the birds breed on land too steep and difficult of access to be of interest to mining or farming. The coastal plain between the colonies and the sea is rich in ilmenite and, for 20 years, mining of ilminite has seemed likely and the processing plant was placed on their major flightpath. Currently it appears that mining will not proceed. Birds are occasionally killed by flying into power pylons, and are attracted to lights and noisy machinery at dawn and dusk. Punakaiki is a growing tourist destination and lights from newly built hotels may pose a threat to the petrels. It is a bycatch species of tuna longliners in New Zealand and Australia, and is exposed to several longline fisheries off the coast of Chile. Birds regularly follow commercial trawlers and may be killed when nets are hauled. Interactions with Patagonian toothfish Dissostichus eleginoides vessels in the Humboldt Current System are also undocumented.