EN
Westland Petrel Procellaria westlandica



Taxonomy

Taxonomic source(s)
Brooke, M. de L. 2004. Albatrosses and Petrels Across the World. Oxford University Press, Oxford.
Christidis, L. and Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood, Australia.
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm#.
Turbott, E.G. 1990. Checklist of the Birds of New Zealand. Ornithological Society of New Zealand, Wellington.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- B2ab(iii) B2ab(iii); D2

Red List history
Year Category Criteria
2018 Endangered B2ab(iii)
2017 Endangered B2ab(iii)
2016 Vulnerable D2
2012 Vulnerable D2
2010 Vulnerable D2
2008 Vulnerable D2
2005 Vulnerable
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

Migratory status full migrant Forest dependency High
Land mass type Average mass -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 30,600,000 medium
Extent of Occurrence breeding/resident (km2) 16 medium
Number of locations 2-5 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 7900-13700 good estimated 2005
Population trend Unknown medium -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations 1 - - -
Largest subpopulations 100 - - -
Generation length (yrs) 30.2 - - -

Population justification: The most recent estimate of population size is 2,954-5,137 annual breeding pairs (Wood and Otley 2013), but given that not all individuals breed each year this is likely to be an underestimate for the number of mature individuals. Assuming that 25% of breeding age birds may skip breeding in any one year (as derived from long-term data sets on similar species) (B. Baker in litt. 2012), the population size is estimated at 7,877-13,698 mature individuals, rounded here to 7,900-13,700 mature individuals.

Following the tropical storm Ita in 2014, there was considerable damage to the breeding area, with the loss or damage of up to 50% of the major colonies, which contain up to 75% of the breeding population (Waugh et al. 2015b). Fortunately, the storm occurred before the laying period and so adults may not have been killed in their nests, unless they were visiting prior to breeding (which some birds have been reported to do) (S. Waugh in litt. 2016), and some birds have moved between impacted colonies (S. Waugh in litt. 2016). Therefore, the level of destruction may not equate to any decline in population, and no population data subsequent to the storm are yet available, though surveys are currently underway (S. Waugh in litt. 2016).

Trend justification: The population was estimated to slowly increase at a rate of 1.8% per year between 1970 and 2012 (Waugh et al. 2015a). However, earlier counts are considered unreliable (S. Waugh in litt. 2017) so the population trend is uncertain.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Argentina V Extant
Australia V Extant Yes
Chile N Extant Yes
New Zealand N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Chile Corriente de Humboldt Arica
New Zealand Canterbury (offshore)
New Zealand Cook Strait
New Zealand East Coast South Island (offshore)
New Zealand Punakaiki
New Zealand West Coast South Island (North) (offshore)

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Temperate major breeding
Marine Neritic Pelagic major non-breeding
Marine Neritic Pelagic major breeding
Marine Oceanic Epipelagic (0-200m) major non-breeding
Marine Oceanic Epipelagic (0-200m) major breeding
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Livestock farming & ranching - Agro-industry grazing, ranching or farming Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Slow, Significant Declines Past Impact
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species mortality
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Unknown Unknown
Stresses
Species mortality
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Unknown Minority (<50%) Negligible declines Unknown
Stresses
Species mortality
Climate change & severe weather Storms & flooding Timing Scope Severity Impact
Past, Likely to Return Majority (50-90%) Causing/Could cause fluctuations Past Impact
Stresses
Ecosystem degradation, Reduced reproductive success, Species mortality
Geological events Avalanches/landslides Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Canis familiaris Timing Scope Severity Impact
Past, Likely to Return Minority (<50%) Causing/Could cause fluctuations Past Impact
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Felis catus Timing Scope Severity Impact
Ongoing Majority (50-90%) No decline Low Impact: 5
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Sus domesticus Timing Scope Severity Impact
Future Majority (50-90%) Rapid Declines Low Impact: 5
Stresses
Ecosystem degradation, Species mortality
Pollution Excess energy - Light pollution Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Reduced reproductive success, Species mortality

Recommended citation
BirdLife International (2019) Species factsheet: Procellaria westlandica. Downloaded from http://www.birdlife.org on 19/09/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 19/09/2019.