Procellaria aequinoctialis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Procellariiformes Procellariidae

Scientific Name: Procellaria aequinoctialis Linnaeus, 1758
Common Name(s):
English White-chinned Petrel
French Pétrel à menton blanc
Spanish Pardela Gorgiblanca
Taxonomic Source(s): Brooke, M. de L. 2004. Albatrosses and Petrels Across the World. Oxford University Press, Oxford.
Identification information: 55 cm.  Large, black petrel with pale bill.  Sooty-black with variable amount of white on throat and chin. Underside of primaries may appear silvery. Horn or yellow bill, with black between nostrils and bill tip.  Similar spp.  Largest all-dark shearwater or petrel.  Bulkier than Westland Petrel P. westlandica and Black Petrel P. parkinsoni and lacks black bill tip.  Spectacled Petrel P. conspicillata has diagnostic white eye-rings and dark tip to bill.  Voice  Rattles at colony.  Hints  Powerful flight intersperses slow wingbeats and glides.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A4bcde ver 3.1
Year Published: 2017
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): ACAP Secretariat, Barbraud, C., Bugoni, L., Colabuono, F., Cooper, J., Croxall, J., Hirst, P., Makhado, A., Martin, T., Misiak, W., Phillips, R., Rexer-Huber, K., Robertson, C., Ryan, P.G., Small, C. & Taylor, G.A.
Facilitator/Compiler(s): Anderson, O., Ashpole, J, Black, A., Butchart, S., Calvert, R., Martin, R, Moreno, R., Small, C., Taylor, J., Wheatley, H.
This species is classified as Vulnerable because of suspected rapid declines, although almost no reliable estimates of historical populations exist.  Very high rates of incidental mortality in longline fisheries have been recorded in recent decades; the probability that these circumstances will continue, the susceptibility of chicks to predation, and the degradation of breeding habitat indicate that a rapid and on-going population decline is likely.  An updated assessment of the population on South Georgia is needed in order to fully assess the overall trend.

Previously published Red List assessments:

Geographic Range [top]

Range Description:

This species breeds on South Georgia (Georgias del Sur), Prince Edward Islands (South Africa), Crozet Islands, Kerguelen Islands (French Southern Territories), Auckland, Campbell and Antipodes Islands (New Zealand), and in small numbers in the Falkland Islands (Islas Malvinas). Recently revised population estimates give a global population of approximately three million individuals. This is based on estimates of 773,150 breeding pairs on South Georgia in 2007 (ACAP 2012), 23,600 breeding pairs (9,800 to 36,800) on Crozet (Barbraud et al. in litt. 2008), 186,000-297,000 pairs on the Kerguelen Islands (Barbraud et al. 2009), 186,000 (137,000–241,000) breeding pairs on the Auckland Islands (Rexer-Huber et al. 2016a), and c.22,000 (15,000–29,000) breeding pairs on Campbell (Rexer-Huber et al. 2016b). Between 59,000 and 91,000 pairs breed on Antipodes Island (range of two estimates; Sommer et al. 2010, Sommer et al. 2011). At least 55 pairs breed on the Falkland Islands, on Kidney Island, New Island, Top Island and Bottom Island (Reid et al. 2007, Poncet et al. 2012). A survey in 2009 estimated the number of occupied nests to be c. 24,000 (20,000-28,000) on Marion Island and 9,000-15,000 on Prince Edward Island (Ryan et al. 2012). On Bird Island (South Georgia), the population has apparently decreased by 28% over 20 years (Berrow et al. 2000), while in Prydz Bay (Antarctica), the number of birds at sea decreased by 86% during 1981-1993 (Woehler 1996). The species forages as far north as equatorial waters and south to the pack-ice edge off Antarctica (Berrow et al. 2000, Catard et al. 2000, Phillips et al. 2006, Rexer-Huber et al. in litt. 2016), and is distributed widely in all southern oceans (Croxall et al. 1984).

Countries occurrence:
Antarctica; Argentina; Australia; Brazil; Chile; Ecuador; Falkland Islands (Malvinas); French Southern Territories; Heard Island and McDonald Islands; Madagascar; Mozambique; Namibia; New Zealand; Peru; Saint Helena, Ascension and Tristan da Cunha; South Africa; South Georgia and the South Sandwich Islands; Uruguay
Present - origin uncertain:
Bouvet Island
Additional data:
Estimated area of occupancy (AOO) - km2:3300Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:173000000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:11-100Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):420
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:A global population of 1,200,000 breeding pairs, down from 1,430,000 pairs in the 1980s, is estimated based on figures from 1985-2011. This equates to an estimated global population of c.3 million mature individuals, based on the estimated number of breeding pairs extrapolated according to a ratio from Brooke (2004).

Trend Justification:  Globally, data on long-term trends are still lacking for most colonies. A decline is inferred from a drop in burrow occupancy of 28% over 20 years on Bird Island, South Georgia (Berrow et al. 2000), and declines of 86% during 1981-1993 at sea in Prydz Bay, Antarctica (Woehler 1996). Population monitoring on Marion Island between 1996-1997 and 1999-2000 recorded a 14.5% per annum decrease in the population. Data from the Crozet archipelago indicate a 37% decline in breeding pairs between 1983 and 2004, based on population models and field estimates from two surveys (Barbraud et al. in litt. 2008). At-sea surveys in the Southern Indian Ocean suggest a 35% decline during 1981-2007 (Péron et al. 2010a), and data from fisheries and a population model suggest that the population on the Kerguelen Islands may be in decline (Barbraud et al. 2009). No population trend estimates are available from the Auckland, Campbell, Antipodes or Prince Edward Islands, representing approximately 17% of the global population.

Even when colonies on Auckland, Campbell, Antipodes, Prince Edward and Kerguelen are assumed to be stable, based on an ongoing 1.6% decline per year on South Georgia (ACAP 2009) and declines in the smaller population on Crozet, the overall global population is projected to decline by 52% over three generations from 1980 (C. Small and W. Misiak in litt. 2013). Martin et al. (2009) estimate a higher decline rate for South Georgia (-1.9% per annum), and if the population on Kerguelen was suspected to be declining then the rate of overall population decline could be higher. An updated assessment of the population on South Georgia is needed in order to fully assess the overall trend (ACAP Secretariat in litt. 2013).

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:2400000Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:2-100Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:

It is a burrow-nesting annual breeder, laying in mid-October to mid-November (ACAP 2009). Chicks usually fledge in late April (Barbraud et al. 2009). Outside the chick-rearing period, White-chinned Petrels breeding on South Georgia travel to Patagonian Shelf waters to feed. Falkland Island White-chinned Petrels also largely winter in the Patagonian Shelf waters, but some migrate to waters off southern Chile (Phillips et al. 2006, Rexer-Huber et al. in litt. 2016). Satellite tracking and ring recoveries from birds on Crozet Islands show that they spend the non-breeding season off the coasts of South Africa and Namibia (Barbraud in litt. 2008), while non-breeding birds from Marion Island winter mainly off South Africa (GLS; Rexer-Huber et al. in litt. 2016). Individuals from the Kerguelen Islands also winter off the coasts of South Africa and Namibia over the Benguela Current (Péron et al. 2010a). Non-breeding white-chinned petrels from the Auckland Islands winter off the coast of Peru, Ecuador and northern Chile (Rexer-Huber et al. in litt. 2016), while those from the Antipodes winter off Peru and Chile (Sommer et al. 2010).

It feeds on cephalopods, crustaceans and fish (Berrow et al. 1999, Catard et al. 2000, Delord et al. 2010) and fisheries processing waste or discarded longline baits. Birds range widely when searching for food resources, travelling up to 8,000 km on feeding forays in the breeding season (Berrow et al. 2000, Catard et al. 2000, Phillips et al. 2006, Delord et al. 2010a). Individuals breeding at the Crozet and Kerguelen islands display a bimodal foraging strategy, conducting either short trips to the surrounding shelf or long trips ranging from subtropical waters in the north to Antarctic waters in the south (Catard et al. 2000). Individuals breeding at the Kerguelen Islands target the seasonal ice zone where melting sea ice is gradually broken into floes and forage almost exclusively in open water (Péron et al. 2010b). 

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):24.7
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): This species constitutes the majority of bird bycatch in Southern Ocean longline fisheries. It is thought that fishery-related mortality exerts a greater pressure on the Indian Ocean population than the Atlantic Ocean population (Ryan et al. 2012). It is one of the commonest species attending longline vessels off south-east Brazil during winter (Olmos 1997, Bugoni et al. 2008) and off Uruguay (Jiménez et al. 2009), and constitutes virtually all the recorded seabird bycatch from the Namibian hake fishery (Barnes et al. 1997, Petersen et al. 2007). In South Africa, White-chinned Petrels constitute 10% and 55% of the bycatch in pelagic and demersal longline fisheries respectively (Petersen et al. 2007). Prior to the introduction of bird streamer lines as a vessel permit condition in August 2006, approximately, 10% of the 18,000 birds killed annually in the South African hake trawl fishery were White-chinned Petrels (Watkins et al. 2007), with the species attending 99% of trawls (Hill 2007). In the Indian Ocean, between 2001 and 2003 the legal longline fishery for Patagonian toothfish Dissostichus eleginoides killed c.12,400 P. aequinoctialis per year (Delord et al. 2005). Following the introduction of mitigation measures this figure dropped to approximately 2,500 birds in the 2005-2006 season (CCAMLR 2006), and to 740 birds in the 2008-2009 season (CCAMLR 2010). In addition, an estimated 31,000-111,000 and 50,000-89,000 seabirds in 1997 and 1998 respectively, c.60% of which were P. aequinoctialis, were thought to be killed by IUU vessels (CCAMLR 1997, 1998). In recent years (2006) this figure has fallen to 4,583 seabirds in total (CCAMLR 2006).

It is the second most commonly-caught species in the Argentinean longline fleet, with an average capture rate for the period 1999-2003 of 0.014 ± 0.09 individuals per 1,000 hooks (Laich and Favero 2007). During autumn-winter most captures took place in the north of the Patagonian Shelf, whereas in spring-summer most were to the south, between 45-50 degrees South (Laich and Favero 2007). In the Australian Fishing Zone, more than 800 are potentially killed annually (Gales et al. 1998) and in New Zealand between 2003 and 2005, 14.5% of all the seabirds caught in trawl and longline fisheries and returned for autopsy were P. aequinoctialis (Baird and Smith 2007). Barbraud et al. (2009) estimated that any additional source of mortality that approaches 31,000 individuals would result in a population decline at the Kerguelen Islands. Although only 30% of this number are killed in local waters, and even fewer are now killed due to the implementation of mitigation measures, more than 31,900 White-chinned Petrels are estimated to be killed each year by demersal longline fishing in the Benguela Current marine ecosystem where individuals from the Kerguelen Islands spend the winter. This may mean that the population at the Kerguelen Islands is decreasing, although the additional presence of non-breeders from the Crozet Islands at the Benguela Current means that further research is required to confirm the population decline (Barbraud et al. 2009). Dillingham and Fletcher (2011) estimated that the potential for the world population to sustain additional mortality was 15,000 individuals.

Rats (Rattus rattus and R. norvegicus) are significant predators at some breeding sites, such as Crozet (Jones et al. 2008) and South Georgia (Clarke et al. 2012), and cats predate nests at Kerguelen (Barbraud in litt. 2008), Cochons Island (Crozets) and Marion Island (Carboneras et al. 2014). At South Georgia, breeding habitat is extensively degraded owing to erosion by expanding populations of Antarctic fur seal Arctocephalus gazella (Berrow et al. 2000). Introduced reindeer Rangifer tarandus also degraded breeding habitat on South Georgia (Poncet 2007), but have now been eradicated. Human exploitation is thought to be responsible for extinction on the Chatham Islands (Carboneras et al. 2014). Although no adverse effects have been proven until recently, there are now reports of relatively high frequencies of plastic ingestion (Ryan 2008, Colabuono et al. 2009), as well as the occurrence of persistent organic pollutants (Colabuono et al. 2012) in this species. 

Conservation Actions [top]

Conservation Actions: Conservation and Research Actions Underway
CMS Appendix II ACAP Annex 1.  Population monitoring and foraging ecology studies are being undertaken at South Georgia, Crozet, Prince Edward and Kerguelen (Poncet 2007).  Several breeding sites are in protected areas.

Conservation and Research Actions Proposed

Continue and extend monitoring studies.  Where feasible, eliminate alien predators and reindeer from breeding islands. Promote adoption of best-practice mitigation measures in all fisheries within the species range, including via intergovernmental mechanisms such as ACAP, FAO, and Regional Fisheries Management Organisations such as CCAMLR. Develop and implement plans to remove pigs from Auckland Island, rats, cats and reindeer from Kerguelen, and rats from Ile de la Possession, Crozet (Phillips et al. 2016).

Amended [top]

Amended reason: Edited: Rationale, Population Justification, Trend Justification, Geographic Range, extent of occurrence (EOO), Habitat and Ecology, Threats, Conservation Actions proposed. The estimated number of mature individuals were altered. Added references and also added a new Facilitator and a new Contributor.

Citation: BirdLife International. 2017. Procellaria aequinoctialis (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2017: e.T22698140A112245853. . Downloaded on 18 August 2018.
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