South Georgia Diving Petrel
Pelecanoides georgicus
Number Of Mature
Individuals (Regional)
Unknown
Regional
Population Trend
Decreasing
2025
Regional Category
Near Threatened
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CONTENTSOverview
Names
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IOC English Name: |
South Georgia Diving Petrel |
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SA & IOC Scientific Name: |
Pelecanoides georgicus |
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BirdLife International Taxonomy (scientific name): |
Pelecanoides georgicus |
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Order: |
PROCELLARIIFORMES |
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Family: |
Procellariidae |
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Species name author: |
Murphy and Harper 1916 |
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Afrikaans: |
Suid-Georgië Seeduiker |
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Sesotho (South Africa): |
Seqwelana sa molomoholo |
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Sesotho (Lesotho): |
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Siswati: |
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Zulu: |
umantantotshuzayo waseNingizimu |
Current Assessment Status
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2025 Regional Category [Criteria] |
NT° [A3e; D2] |
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2024 Global Category [Criteria] |
LC |
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Population size (Regional) |
Unknown |
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Population size (Global) |
15 million mature individuals (Brooke 2004) |
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Distribution size (EOO) (Regional) km2 |
c. 720 (breeding) |
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Distribution size (EOO) (Global) km2 |
16 300 000 (breeding/resident) |
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Distribution size (AOO) (Regional) km2 |
334 (breeding) |
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Generation time |
6.24 years (Bird et al. 2020) |
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Status change reason |
No Change |
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Migrant (in the region) |
No |
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Regional endemic |
No |
Historic Listing Information
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2000 Regional Status |
LC |
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2015 Regional Status |
NT [D2] |
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Status change reason (if applicable) |
Changes in Assessment Process |
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2015 Population size (Regional) |
Unknown |
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2015 Global Status |
LC |
Reason for Inclusion
Reason for Inclusion in the Assessment
The species breeds on the Prince Edward Islands in the region and was classified as Near Threatened in 2015 (Madden and Wanless 2015). The global population estimates are based on dated data, while uncertainty exists around the regional population, complicating the application of the 5% regional filter. Adopting a cautionary approach the species was assessed.
Category Justification
Category Justification
The regional population of South Georgian Diving Petrel Pelecanoides georgicus satisfies the criterion for regionally Vulnerable under D2 given the low reported sightings of the species on Marion Island, and probable vulnerability to mouse predation, and the dearth of knowledge on population size on Prince Edward Island. Furthermore, the species qualifies for Vulnerable under Criterion A3 due to projected future declines based on expert-assessed extinction horizons due principally to the threat of House Mice Mus musculus on Marion Island (Preston et al. 2019). While there is limited direct evidence of ongoing population decline currently, predictive assessments suggest that the species may experience a significant reduction over the next three generations. The extinction horizon estimates indicate that the species’ population may decline by 40.3% within this period, exceeding the threshold for Vulnerable under A3 (Lee 2025).
Since a Regional Rescue Effect is applicable given the pelagic nature of the species, plus a non-threatened global population, the Category is modified to: NTo [A3e; D2].
Population Justification
The global population is estimated at 15 million mature individuals (Brooke 2004). Rand (1954) reported the South Georgian Diving Petrel to be ‘commonly found’ on Marion Island in 1948, but after the introduction of cats in the same year, numbers collapsed. In 1979 only 44 burrows were located in 21 ha (Schramm 1986). In 2011, the first confirmed breeding attempt on Marion Island in 32 years was recorded (McClelland et al. 2013) but the species remains scarce there (Dilley et al. 2017). The Prince Edward Island population has not been impacted by introduced predators. However, little is known about population estimates although breeding populations are suspected (Barnes and Huyser 1998, McClelland et al. 2013).
Trend Justification
The global population is thought to be decreasing (BirdLife International 2019). Regionally, on Marion Island, the trend was thought to be positive due to the removal of domestic cats Felis catus (Cooper et al. 1995, Ryan and Bester 2008) but reported breeding attempts remain scarce (McClelland et al. 2013, Dilley et al. 2017). Data on the suspected breeding population on Prince Edward Island is insufficient to detect a trend. As such, the regional population trend is uncertain. Future population projections based on extinction horizon estimates suggest that significant reductions may occur within the next three generations (Preston et al. 2019). While no significant recent declines have been observed, the potential for future declines justifies careful consideration under Criterion A3 (Lee 2025). Ongoing monitoring is essential to validate these projections and determine whether the species is experiencing measurable population decreases.
Biology & Ecology
Taxonomy
The species is monotypic. Genetic data suggest that populations in New Zealand and the Indian Ocean may differ at subspecies level from those in the South Atlantic (Onley and Scofield 2007).
Identification
18–21 cm, 90–150 g. The South Georgian Diving Petrel is characterized by its small size, short neck, and relatively long tail. Its underparts are predominantly white, with a clear demarcation between the dark cap and the white throat. It also features a short, wide dusky collar and white underwings with pale grey remiges. In fresh plumage, a distinctive white crescent curls up behind the eye. Key identifying traits include white borders on the scapulars that create two distinct lines down its back, as well as white fringes on the tips of the inner flight feathers and coverts. The bird possesses a stubby-hooked black bill that broadens at the base, gradually converging, with short nasal tubes and upward-facing nostrils. Its legs and feet exhibit a bluish hue, with a posterior black line running down the tarsi and black toes and webs (del Hoyo et al. 1992, Onley and Scofield 2007, Chester 2010).
Distribution
The South Georgian Diving Petrel has a circumpolar distribution, with two distinct populations breeding in the Atlantic Ocean (on South Georgia and surrounding islets) and western Indian Ocean (Prince Edward, Marion, Crozet, Kerguelen, McDonald and Heard islands) (del Hoyo et al. 1992, Onley and Scofield 2007). There was a New Zealand population which was recently found to be significantly different from the other populations, meriting species status (Fischer et al. 2018). While these birds are likely to be sedentary, there have been observations and records from Australia and south of Cape Horn suggesting some level of dispersion (Onley and Scofield 2007).
Ecology
The South Georgian Diving Petrel engages in its breeding activities from October to February (del Hoyo et al. 1992). During this period, they construct burrows on high-altitude cinder slopes (McClelland et al. 2013). It is worth noting that burrows found on high-elevation scree slopes at Prince Edward Island are believed to be attributed to either this species or the Common Diving Petrel (RM Wanless pers obs). These birds have an estimated generation length of 6.24 years (Bird et al. 2020). Breeding likely commences in the second year, with females producing one egg per season. The incubation period for these eggs span from 44 to 52 days (del Hoyo et al. 1992).
South Georgian Diving Petrels primarily obtain their prey by diving to an average depth of 26 meters (Bocher et al. 2000). Their diet predominantly consists of crustaceans, although they will also consume copepods and small fish (del Hoyo et al. 1992). These petrels exhibit nocturnal behaviour at their colonies, returning to them at night after foraging to avoid potential predation by skuas and gulls (Bocher et al. 2000, Perrins 2003).
Diving Petrels belong to the group of tiny Procellariiformes. They have made an evolutionary trade-off, sacrificing aerial flying ability for exceptional underwater propulsion. This adaptation has resulted in their unique shape and extremely rapid wingbeats. Their wing area is optimized for underwater propulsion rather than generating lift for aerial flight (Warham 1977).
Threats & Conservation
Threats
Introduced predators on breeding islands, and being hunted by humans for their feathers are the main threats to the South Georgian Diving Petrel (BirdLife International 2019). The Marion Island population was severely impacted by cats, however this threat was removed when the last cat was eradicated in 1991 (Bester et al. 2002). Despite this, no active burrows were recorded until 2011 (McClelland et al. 2013), showing the slow recovery from cat predation, and perhaps an indication that other unknown threats are preventing this population from recovering. The population is considered vulnerable to predation by invasive rodents on Marion Island, with Dilley (2018) estimating 50 years to local extirpation sans eradication. Prince Edward Island is free from introduced predators (de Villiers and Cooper 2008) and although breeding there has not been confirmed, there are no known threats to the suspected breeding population.
Conservation Measures Underway
At present, there are no conservation measures specifically tailored to this particular species. However, several general conservation initiatives have been implemented at its breeding islands. The Prince Edward Islands have been designated as a Ramsar Wetland of International Importance. They also hold the status of a Special Nature Reserve under the Environment Conservation Act (No. 73 of 1989) and are governed by the Prince Edward Islands Management Plan from 1996. Additionally, the Prince Edward Islands Marine Protected Area was established and officially declared in 2013 as part of broader conservation efforts which benefit the species. Mouse eradication is being planned.
Conservation Measures Proposed
Filling the data deficiencies mentioned below is recommended.
Research Priorities and Questions
- Information is required on population numbers and trends on Marion and Prince Edward islands.
- Virtually nothing is known about many basic demographic parameters, at-sea distributions, movements, habitat preferences, or foraging ecology for this species at the Prince Edward islands or elsewhere.
Contributors & References
Assessor/s
Shamiso Banda
Reviewer/s
Stefan Schoombie
References
Barnes KN, Huyser O. 1998. The Prince Edward Islands Important Bird Area. In: Barnes KN (ed). The Important Bird Areas of southern Africa. Johannesburg, South Africa: BirdLife South Africa. pp 269–272.
Bester MN, Bloomer JP, van Aarde RJ, Erasmus BH, van Rensburg PJJ, Skinner JD, Howell PG, Naude TW. 2002. A review of the successful eradication of feral cats from Subantarctic Marion Island, Southern Indian Ocean. South African Journal of Wildlife Research 32: 65–73.
Bird JP, Martin R, Akçakaya HR, Gilroy J, Burfield IJ, Garnett ST, Symes A, Taylor J, Şekercioğlu ÇH, Butchart SH. 2020. Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology 34: 1252–1261.
BirdLife International. 2019. Pelecanoides georgicus. The IUCN Red List of Threatened Species 2019: e.T155187102A155188668. Available: https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T155187102A155188668.en. [Accessed on 12 September 2023].
Bocher P, Cherel Y, Hobson KA. 2000. Complete trophic segregation between South Georgian and Common Diving petrels during breeding at Iles Kerguelen. Marine Ecology Progress Series 208: 249–264.
Brooke MD. 2004. Albatrosses and Petrels Across the World (Bird Families of the World). Oxford, United Kingdom: Oxford University Press.
Chester S. 2010. A Wildlife Guide to Chile: Continental Chile, Chilean Antarctica, Easter Island, Juan Fernandez Archipelago. Princeton, United States of America: Princeton University Press.
Cooper J, Marais A, Bloomer JP, Bester MN. 1995. A success story: breeding of burrowing petrels (Procellariidae) before and after the eradication of feral cats Felis catus at subantarctic Marion Island. Marine Ornithology 23: 33–37.
de Villiers MS, Cooper J. 2008. Conservation and management. In: Chown SN, Froneman W (eds), The Prince Edward Islands: land-sea interactions in a changing ecosystem. Stellenbosch, South Africa: African Sun Media. pp 301–330.
del Hoyo J, Elliot A, Sargatal J. 1992. Handbook of the Birds of the World, Vol 1: Ostrich to Ducks. Barcelona, Spain: Lynx Edicions.
Dilley BJ, Schramm M, Ryan PG. 2017. Modest increases in densities of burrow-nesting petrels following the removal of cars (Felis catus) from Marion Island. Polar Biology 40: 625–637.
Dilley BJ. 2018. The effects of introduced mice on seabirds breeding at sub-Antarctic Islands. PhD thesis: University of Cape Town.
Fischer JH, Debski I, Miskelly CM, Bost CA, Fromant A, Tennyson AJD, Tessler J, Cole R, Hiscock JH, Taylor GA, Wittmer HU. 2018. Analyses of phenotypic differentiations among South Georgian Diving Petrel (Pelecanoides georgicus) populations reveal an undescribed and highly endangered species from New Zealand. PLoS ONE 13(6): e0197766.
Lee ATK. 2025. The application of IUCN Regional Red List Criteria to the species of South Africa’s Prince Edward Islands. Unpublished report. Johannesburg: BirdLife South Africa.
Madden CF, Wanless RM. 2015. South Georgia Diving Petrel. In: Taylor MR, Peacock F, Wanless RW (eds), The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland. Johannesburg, South Africa: BirdLife South Africa. pp 353–354.
McClelland GTW, Cooper J, Chown SL. 2013. Evidence of breeding by Diving Petrels and Storm Petrels at Marion Island after the eradication of feral cats. Ornithological Observations 4: 90–93.
Onley D, Scofield P. 2007. Albatrosses, Petrels and Shearwaters of the World. London, United Kingdom: A&C Black.
Perrins CM. 2003. The new encyclopedia of birds. Oxford, United Kingdom: Oxford University Press.
Preston GR, Dilley BJ, Cooper J, Beaumont J, Chauke LF, Chown, SL, Devanunthan N, Dopolo M, Fikizolo L, Heine J, Henderson S, Jacobs CA, Johnson F, Kelly J, Makhado AB, Marais C, Maroga J, Mayekiso M, McClelland G, Mphepya J, Muir D, Ngcaba N, Ngcobo N, Parkes JB, Paulsen F, Schoombie S, Springer K, Stringer C, Valentine H, Wanless RM, Ryan PG. 2019. South Africa works towards eradicating introduced house mice form the sub-Antarctic Marion Island: the largest island yet attempted for mice. In: Island Invasives: Scaling up to Meet the Challenge. Veitch CR, Clout MN, Martin AR, Russell JC, West CJ (eds), Occasional Paper of the IUCN Species Survival Commission; Vol. 62 pp 40–46. IUCN. https://portals.iucn.org/library/node/48358.
Rand RW. 1954. Notes on the birds of Marion Island. Ibis 96: 173–206.
Schramm M. 1986. Burrow densities and nest site preferences of petrels (Procellariidae) at the Prince Edwards Islands. Polar Biology 6: 63–70.
Warham, J. 1977. Wing loadings, wing shapes, and flight capabilities of Procellariformes. New Zealand Journal of Zoology 4(1): 73–83.
Citation
Banda S 2025. South Georgia Diving Petrel. In: Lee ATK, Rose S, Banda S, Bezeng SB, Maphalala MI, Maphisa DH, Smit-Robinson H (eds), The 2025 Red Data Book of Birds of South Africa, Lesotho and Eswatini. Johannesburg, South Africa: BirdLife South Africa. Available at: https://www.birdlife.org.za/red-list/south-georgia-diving-petrel/
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