Westland Petrel (Procellaria westlandica)

Westland Petrel

[order] PROCELLARIIFORMES | [family] Procellariidae | [latin] Procellaria westlandica | [authority] Falla, 1946 | [UK] Westland Petrel | [FR] Puffin du Westland | [DE] Westland-Sturmvogel | [ES] Pardela de Westland | [NL] Westlandstormvogel


Monotypic species


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.

Physical charateristics

Large, black petrel. Undersides of primaries may appear silvery. Yellowish bill, whiter in juveniles, has black tip. Black legs, feet. Larger than southern hemisphere shearwaters. Black Petrel P. parkinsoni becomes browner as ages, is smaller, especially bill. Differs from White-chinned Petrel P. aequinoctialis in black-tipped bill, absence of white chin

Listen to the sound of Westland Petrel

[audio:http://www.planetofbirds.com/MASTER/PROCELLARIIFORMES/Procellariidae/sounds/Westland Petrel.mp3]

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
broods: 1   eggs min.: 1  
      eggs max.: 1  


Pacific Ocean : Southwest. Procellaria westlandica breeds in the densely forested coastal foothills at Punakaiki, South Island, New Zealand


They nest on densely forested hills between 20-250 m. Burrows are usually concentrated in areas where the ground is relatively open, and where take-off areas are close by.


They build large, cavernous burrows in colonies, up to 2 m long, close to steep slopes, cliff edges or trees from where they can take off. In May, one egg is laid in the burrow and incubated for 57 to 65 days. Chicks fledge after 120 to 140 days and then head out to the open ocean, not returning to the colony for five years, and not breeding themselves until, on average, the age of ten.

Feeding habits

Fisheries waste is an important dietary component, perhaps forming more than half of solid food eaten during the hoki fishing season. Subsequent satellite tracking studies have suggested that dietary analysis over-estimates the amount of food scavenged from trawlers and that the species continues to forage over wider areas than those occupied by the hoki fishery. Even individuals known to forage at fishing fleets take a large proportion of their food elsewhere.

Video Westland Petrel


copyright: Brooke Clibbon


This species qualifies as Vulnerable because it is restricted to one very small area when breeding, rendering the population highly vulnerable to stochastic events and other potential threats.
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.
Westland Petrel status Vulnerable


At close of breeding season birds migrate E of New Zealand into C Pacific, some reaching W South America; young birds may spend up to 10 years in zone of Humboldt Current. Small numbers cross Tasman Sea to E Australia; perhaps mainly young birds.

Distribution map

Westland Petrel distribution range map

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