Procellaria westlandica

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

View Printer Friendly

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PROCELLARIIFORMES	PROCELLARIIDAE

Scientific Name:

Procellaria westlandica

Species Authority:

Falla, 1946

Common Name/s:

English

–

Westland Black Petrel, Westland Petrel

Assessment Information [top]

Red List Category & Criteria:

Vulnerable D2 ver 3.1

Year Published:

2010

Assessor/s:

BirdLife International

Reviewer/s:

Calvert, R., Butchart, S., Bird, J.

Contributor/s:

Tennyson, A., Wilson, K.

Justification:
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.

History:

2008	–	Vulnerable
2005	–	Vulnerable
2004	–	Vulnerable
2000	–	Vulnerable
1996	–	Vulnerable
1994	–	Vulnerable

Geographic Range [top]

Range Description:	Procellaria westlandica breeds in the densely forested coastal foothills at Punakaiki, South Island, New Zealand¹. In 1958, the population was estimated at 3,000-6,000 birds, in 1972, 6,000-10,000 birds, and in 1982, 1,000-5,000 pairs⁴. In 1974, however, only 818 occupied burrows were located¹. Recent estimates put the total population at less than 20,000 birds, and c.4,000 pairs^3,5,12,15. Population modelling suggests a decline in numbers since 1985⁹. However, none of the population estimates are of high quality. It migrates in summer to central Pacific and eastern New Zealand waters, east coast of Australia and off South America^4,7, and is regularly recorded off the coast of Chile extending into the South Atlantic to the east of Tierra del Fuego¹⁰.
Countries:	Native: Chile; New Zealand; United States; United States; United States; United States Vagrant: Argentina; Australia
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	The population numbered c.20,000 individuals in 1982 and has remained stable, with c. 2,000 pairs breeding annually (Heather and Robertson 1997; Adams 1998; Taylor 2000).
Population Trend:	Stable

Population:

The population numbered c.20,000 individuals in 1982 and has remained stable, with c. 2,000 pairs breeding annually (Heather and Robertson 1997; Adams 1998; Taylor 2000).

Population Trend:

Stable

Habitat and Ecology [top]

Habitat and Ecology:	Behaviour The species is a colonial, winter breeder. Most eggs are laid in May, and hatch mostly in the last half of June. Chicks fledge from November to January¹⁵. In any given year, a large proportion of the population skip breeding, however, there is no discernable pattern to this behaviour although it maybe linked with El Niño events ¹¹. Skipped breeders have lower survival rates, possibly due to differences in the 'fitness' of individuals, although this could be biased by emigration. Juveniles return to the colony as young as three years, but the age of first breeding is six to seven years ¹¹. During chick-rearing, satellite-tracking data indicate foraging principally on the continental slope off the West Coast of South Island, with one trip undertaken through Cook Strait to the Chatham Rise east of South Island¹⁵. Habitat Breeding 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. Diet Fisheries waste is an important dietary component, perhaps forming more than half of solid food eaten during the hoki fishing season². 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 ^{8, 9}.
Systems:	Terrestrial; Marine

Habitat and Ecology:

Behaviour The species is a colonial, winter breeder. Most eggs are laid in May, and hatch mostly in the last half of June. Chicks fledge from November to January¹⁵. In any given year, a large proportion of the population skip breeding, however, there is no discernable pattern to this behaviour although it maybe linked with El Niño events ¹¹. Skipped breeders have lower survival rates, possibly due to differences in the 'fitness' of individuals, although this could be biased by emigration. Juveniles return to the colony as young as three years, but the age of first breeding is six to seven years ¹¹. During chick-rearing, satellite-tracking data indicate foraging principally on the continental slope off the West Coast of South Island, with one trip undertaken through Cook Strait to the Chatham Rise east of South Island¹⁵. Habitat Breeding 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. Diet Fisheries waste is an important dietary component, perhaps forming more than half of solid food eaten during the hoki fishing season². 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 ^{8, 9}.

Systems:

Terrestrial; Marine

Threats [top]

Major Threat(s):	Introduced mammals and the native Weka Gallirallus australis prey on eggs, chicks and adults, goats trample burrows, and contribute to the erosion of subcolonies^1,4,5,6,11. 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 farming¹⁴. 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 proceed¹⁴. Birds are occasionally killed by flying into power pylons, and are attracted to lights and noisy machinery at dawn and dusk⁵. 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 Australia³, and is exposed to several longline fisheries off the coast of Chile. Birds regularly follow commercial trawlers and may be killed when nets are hauled⁵. Interactions with Patagonian toothfish Dissostichus eleginoides vessels in the Humboldt Current System are also undocumented¹⁵.

Major Threat(s):

Introduced mammals and the native Weka Gallirallus australis prey on eggs, chicks and adults, goats trample burrows, and contribute to the erosion of subcolonies^1,4,5,6,11. 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 farming¹⁴. 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 proceed¹⁴. Birds are occasionally killed by flying into power pylons, and are attracted to lights and noisy machinery at dawn and dusk⁵. 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 Australia³, and is exposed to several longline fisheries off the coast of Chile. Birds regularly follow commercial trawlers and may be killed when nets are hauled⁵. Interactions with Patagonian toothfish Dissostichus eleginoides vessels in the Humboldt Current System are also undocumented¹⁵.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway CMS Appendix II and ACAP Annex 1. The breeding site is within the Paparoa National Park. A proposal to designate the colonies as the Westland Petrel Special Area was approved in 1999, and will restrict public access. A long-term study has been in place since 1969, covering social organisation, behaviour, breeding biology and aspects of population dynamics. A demographic study was undertaken between 1995 and 2003 ¹¹. Predator and herbivore control has been carried out in the main breeding colonies since 1990⁵. A survey of all breeding colonies and a new estimate for the breeding population is planned in 2009-2010. Research on species vocalisations, foraging behaviour and at sea movements is currently in progress¹³. Conservation Actions Proposed Census all burrows every 10 years. Continue annual monitoring of study burrows, and band chicks and adults. Identify and minimise hazards to birds flying to and from the colony. Continue sustained predator control and monitoring of nests to identify predation events, and respond accordingly. Continue sustained control of browsing mammals, particularly goats and possums. Fence colony boundaries to exclude stock⁵. Minimise impact of tourist infrastructure through planning control¹⁴.

Conservation Actions:

Conservation Actions Underway
CMS Appendix II and ACAP Annex 1. The breeding site is within the Paparoa National Park. A proposal to designate the colonies as the Westland Petrel Special Area was approved in 1999, and will restrict public access. A long-term study has been in place since 1969, covering social organisation, behaviour, breeding biology and aspects of population dynamics. A demographic study was undertaken between 1995 and 2003 ¹¹. Predator and herbivore control has been carried out in the main breeding colonies since 1990⁵. A survey of all breeding colonies and a new estimate for the breeding population is planned in 2009-2010. Research on species vocalisations, foraging behaviour and at sea movements is currently in progress¹³.

Conservation Actions Proposed
Census all burrows every 10 years. Continue annual monitoring of study burrows, and band chicks and adults. Identify and minimise hazards to birds flying to and from the colony. Continue sustained predator control and monitoring of nests to identify predation events, and respond accordingly. Continue sustained control of browsing mammals, particularly goats and possums. Fence colony boundaries to exclude stock⁵. Minimise impact of tourist infrastructure through planning control¹⁴.

Citation:	BirdLife International 2010. Procellaria westlandica. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 24 May 2012.
Disclaimer:	To make use of this information, please check the <Terms of Use>.
Feedback:	If you see any errors or have any questions or suggestions on what is shown on this page, please fill in the feedback form so that we can correct or extend the information provided