Great Shearwater Ardenna gravis Scientific name definitions

This species account is dedicated in honor of Alexander Ellis III, member of the Cornell Lab of Ornithology's Administrative Board.

Editor's Note: This is a shorter format account, originally published in HBW Alive. Please consider contributing your expertise to update and expand this account.

This large shearwater is easily identified by its distinctive plumage, marked by the dark cap and brown belly-patch, with the white underwing also relieved by variable brown markings. The Greater Shearwater breeds in very small numbers on one island in the Falkland Islands, but is otherwise confined as a breeding bird to Tristan da Cunha and the seabird ‘hotspot’ of Gough, where an estimated five million pairs breed. Given such exceptional abundance, it is unsurprising that harvesting of this species by local people has continued relatively unabated since historical times. During the non-breeding season, the Greater Shearwater moves north in April and May, reaching as far north as Newfoundland and even Greenland, and moving south again, apparently mainly through the eastern Atlantic in August to October, although it should be mentioned that small numbers apparently remain in the South Atlantic all year.

43–51 cm; 670–995 g (1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ); wingspan 100–118 cm. Large drab and white, dark-capped shearwater, with blackish bill . Cap to gape-level and back to nape rather cold sooty-brown, can have diffuse partial or complete whitish eyering, often appearing quite dark at sea and strongly contrasting with bold white collar, sometimes incomplete at hindneck, rest of upperparts including upperwing grey-brown or brown with pale fringes giving bird scaly pattern except white rearmost uppertail-coverts, primary-coverts slightly darker brownish and less scaly, remiges slightly darker and greyer, rear scapulars and tertials dark but dorsal pattern usually does not form well-defined transversal M; uppertail  blackish brown; underwing has dark greyish tips to remiges forming obvious trailing edge , broader at wingtip, bases of remiges and most of coverts white, dark stripes and spots on lesser and median coverts form variable dark contrasting pattern on axillaries and at leading edge of wing; partial brownish collar from upper mantle to sides of upper chest, rest of underparts white except diffuse and sometimes weak brownish patch or smudging on central belly and on thighs and undertail-coverts; iris dark brown; bill blackish grey; legs pink, usually dusky on outer side of tarsus and outer toe. Sexes alike, but female averages slightly smaller. Juvenile (Jun–Nov) similar to adult, but lacks whitish hindcollar and general plumage fresh in Jun–Jul, but often faded and worn by Sept–Nov; second-cycle birds (May–Aug) can have cap and hindneck pattern varying from adult-like to juvenile-like, and often retain some abraded juvenile outer primaries, while dark belly patch reduced in worn plumage and virtually absent in some (Oct–Dec) (2 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ). Structurally more similar to Calonectris than to most Ardenna shearwaters, but wings slightly more pointed and bill notably slimmer; underparts similar to A. creatopus, but underwing pattern usually better defined, dark patch on central belly, strongly capped appearance and all-dark bill prevent confusion; white horseshoe on rear upperparts may lead to confusion with Calonectris, but often looks greyer and more patterned, and dark slimmer bill and capped appearance are distinctive; some large, capped Pterodroma may look superficially similar, but bill shape, dark forehead and underwing pattern prevent confusion.

Atlantic Ocean and SW Indian Ocean, breeding on Nightingale I and Inaccessible I (Tristan da Cunha), on Gough I, and on Kidney I (in Falklands).

Marine, frequenting cool offshore and pelagic waters. Breeds on sloping ground  , mainly in areas of tussock grass (Spartina arundinacea), ferns (Ctenitis aquilina) or Phylica woodland.

Transequatorial migrant. During breeding season concentrated in waters of S Atlantic (being abundant off Brazil at this time) (3 Olmos, F. (1997). Seabirds attending bottom long-line fishing off southeastern Brazil. Ibis. 139(4): 685–691. Close ) and, to lesser extent, SW Indian Ocean, especially around Subtropical Convergence, over waters of 9–16ºC (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), and is regular visitor to seas around South Georgia (Nov–Apr) (5 Prince, P. A., and J. P. Croxall (1996). The birds of South Georgia. Bulletin of the British Ornithologists’ Club 116(2):81–104. Close ). Post-breeding, adults from Apr, juveniles in May (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), moves NW, passing Bermuda (peak late May/Jun), to reach North America from mid May (mainly until Nov) (2 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ), occasionally as far N as SE Baffin I (2 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ) and Greenland (65º N) (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), and W to Gulf of Mexico (mainly Jun–Oct) and even inland as far as Great Lakes (Ontario) and Tennessee (usually following tropical storms), with comparatively few records in West Indies (6 Pérez-Rivera, R.A. and Miranda, L. (1994). Corroboración de algunos registros de aves para Puerto Rico. El Pitirre. 7(1): 2–3. Close , 7 Hayes, F.E. (1998). Noteworthy bird records for Trinidad & Tobago, 1995-1996. El Pitirre. 11(1): 5–6. Close , 8 Feldmann, P., Benito-Espinal, E. and Keith, A.R. (1999). New bird records from Guadeloupe and Martinique, West Indies. J. Field Orn.. 70(1): 80–94. Close , 2 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ), Middle and N South America (9 Sandoval, L., Sánchez, C., Biamonte, E., Zook, J.R., Sánchez, J.E., Martínez, D., Loth, D. and O’Donahoe, J. (2010). Recent records of new and rare bird species in Costa Rica. Bull. Brit. Orn. Club 13123(4): 237–245. Close ), and others off NE Brazil in May–Jun (10 Cardoso de Sousa, M., Fraga, R.T. and Carlos, C.J. (2005). Seabird records from Alagoas and Sergipe states, north-east Brazil. Cotinga. 24: 112–114. Close ); subsequently at least move E, turning S past Britain and Iberia (occasionally entering Mediterranean, where also recorded Jan, Mar, May, Sept–Dec, E to Greece and Lebanon) (11 Bonaccorsi, G. (2003). Les Procellariiformes (Diomedeidae, Procellariidae et Hydrobatidae) non nicheurs en Méditerranée occidentale: une synthèse [Non-breeding procellariiformes (Diomedeidae, Procellariidae and Hydrobatidae) in the west of the Mediterranean]. Alauda 71(1):1–7. Close , 12 Ramadan-Jaradi, G., Bara, T., Almécija, M. and Ramadan-Jaradi, M. (2004). Significant bird notes from Lebanon during 251512–513. Sandgrouse. 26(1): 29–34. Close , 13 Probonas, N. (2006). The first Great Shearwater for Greece. Birding World. 19(11): 481. Close ), and returning S towards breeding islands via W Africa (Oct–Nov records off Senegal) (14 Marr, T., D. Newell, and R. Porter (1998). Seabirds off Senegal, West Africa. Bulletin of the African Bird Club 5(1):22–28. Close , 15 Strandberg, R. and Olofsson, P. (2007). Sea bird counts at N’Gor, Senegal, in November 252526. Malimbus. 29(2): 128–130. Close ), but others move S through W Atlantic in Sept–Nov, occasionally until Dec, with casual (but perhaps increasing) records in boreal winter/spring off North America, N even to Nova Scotia and Newfoundland (Jan–Apr) (2 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ). Small numbers apparently winter in S Hemisphere (e.g. seen off S Brazil as late as third week of Jun) (16 Olmos, F., Martuscelli, P., Silva, R. and Neves, T.S. (1995). The sea-birds of São Paulo, southeastern Brazil. Bull. Brit. Orn. Club. 115(2): 117–128. Close ), where recorded in extreme S Chile (17 Clark, G. S., A. Cowan, P. Harrison, and W. R. P. Bourne (1992). Notes on the seabirds of the Cape Horn islands. Notornis 39(2):33–144. Close , 18 Howell, S. N. G., and S. Webb (1995) Noteworthy bird observations from Chile. Bulletin of the British Ornithologists' Club 115: 57–66. Close ) (N to 48° S) (19 Spear, L. B., and D. G. Ainley (2008). The seabird community of the Peru Current, 1980–1995, with comparisons to other eastern boundary currents. Marine Ornithology 36(2):125–144. Close ) and is vagrant to SW Pacific (mainly off Australia)—South Australia (possibly same bird, Jan 1989 and Feb 1989), New South Wales (Apr 2006, Mar 2011, Apr 2011, Nov 2011), Victoria (Apr 2011), New Zealand (two, Kermadec Is, one, Cook Strait), between Gambier Is, French Polynesia and New Zealand (Sept 2006) and Chatham Is, New Zealand (Dec 2006) (20 Gaskin, C., Shirihai, H. and Wood, S. (2008). Sightings of great shearwater (Puffinus gravis) near New Zealand in 282826. Notornis. 55(4): 222–223. Close , 21 Palliser, T., and M. Carter (2013). Rare birds: the 2012 BARC report. Australian Birdlife 2(4):50–53. Close )—with N Hemisphere records, mainly since 1990s, from the Pacific off C California (mainly Aug–Oct, also late Nov–Apr) and Gulf of Alaska (Aug 2001) (2 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ).

Mostly fish (e.g. mackeral and capelin) (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), squid (especially Illex illecebrosus off Newfoundland) (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ) and fish offal; also some crustaceans, with breeding-season diet said to be dominated by cephalopods and, to lesser extent, crustacea, but no quantative analysis attempted (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), whereas off Newfoundland, during non-breeding season, crustacea formed between 0% to 30% of diet by weight (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Prey taken mainly by plunge-diving from height of 6–10 m, with dives typically lasting less than 12 seconds (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ); also uses pursuit-diving and surface-seizing. Time-depth recorders have recently been deployed on two females nesting on Inaccessible I, recording ten consecutive days of diving activity, while remote sensing imagery and movement patterns of eight males tracked by satellite telemetry over same period were used to identify probable foraging areas used by the females: the deepest and longest dive was to 18·9 m and lasted 40 seconds, but most (> 50%) dives were < 2 m deep, with diving most frequent near dawn and dusk, and < 0·5% of dives occurred at night; the two birds foraged in contrasting oceanographic conditions, one in cold (8–10ºC) water of the Subantarctic Front, probably 1000 km S of the colony, the other in warmer (10–16ºC) water of the Subtropical Frontal Zone, possibly on the Patagonian Shelf, 4000 km away, with the cold-water bird conducting four times as many dives as the warm-water bird, diving deeper on average, and spending a greater proportion of bottom time during dives (22 Ronconi, R.A., Ryan, P.G., Ropert-Coudert, Y. (2010). Diving of Great Shearwaters (Puffinus gravis) in cold and warm water regions of the South Atlantic Ocean. PLOS One. 5(11): e15508. Close ). Forages over Sargassum in NW Atlantic, but does not specialize in this (23 Moser, M .L. and D. S. Lee (2012) Foraging over Sargassum by western North Atlantic seabirds. Wilson Journal of Ornithology 124: 66–72. Close ). Attends trawlers (24 Valeiras, J. (2003). Attendance of scavenging seabirds at trawler discards off Galicia, Spain. Scientia Marina 67(Supplement 2):77–82. Close ), sometimes in large numbers and with other seabirds (including other shearwaters and Wilson’s Storm-petrels Oceanites oceanicus) (25 Harrison, N. M., M. J. Whitehouse, D. Heinemann, P. A. Prince, G. L. Hunt Jr., and R. R. Veit (1991). Observations of multispecies seabird flocks around South Georgia. Auk 108(4):801–810. Close , 26 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close , 2 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ), and periodically associates with cetaceans (e.g. Atlantic spotted dolphins Stenella frontalis) (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close , 27 Scherer, A.L., Souza Petersen, E., Habkost Schuh, M., Cristofoli, S.I., Mazzini Tavares, C.L., Duarte, A., Petry, M.V. and Sander, M. (2010). Interação entre aves marinhas (Procellariiformes) e golfinhos-pintados-do-atlântico Stenella frontalis (Cetacea: Delphinidae) em águas oceânicas do sudeste do Brasil. Rev. Bras. Orn. 18(3): 234–236. Close ).

Vocalizes mainly on ground, rather than in flight, at colonies, where calling commences in mid afternoon and peaks around dusk (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ); calls described as vigorous and unmelodic, with slight differences between males and females (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Nasal bleating and squawking calls recorded from foraging birds at sea (2 Howell, S. N. G. (2012). Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA. Close ).

Copulation in Oct, returning to colonies in second half of Sept, with probable pre-laying exodus of up to c. 1 month starting in mid to late Oct (1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ), egg-laying on Nightingale I (Tristan da Cunha) in first two weeks of Nov (mean 11 Nov) (26 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ), but peaking later (21 Nov) on Gough (1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ), hatching early to mid Jan, and young vacate colony between late Apr and mid May (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close , 1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ). Less nocturnal at colonies than most shearwaters, as large size reduces the species’ vulnerability to attacks by skuas (Catharacta) (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ). Long-term monogamous pair-bonds and territorial around burrow entrance (26 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ). Highly colonial; nests in self-excavated burrows (up to 1 m long) (26 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ) or crevices among boulders. Single white egg, mean size 80 mm × 51·5 mm (Tristan da Cunha group) (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ) or 78·1 mm × 48·6 mm (1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ); incubation 53–57 days; chicks  have bluish grey down, fed regularly during day (26 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ) (up to 22% of meals were delivered by day on Gough), with mean meal size of 188 g brought every 3–4 days (1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ); fledging c. 105–120 days when 740–1270 g (1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ), probably following long desertion period (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), reaching maximum weight (848–1539 g, c. 150% that of adult) at 56–90 days (1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ). On Gough I, in 2000/01 season, overall breeding success was 66%, with hatching success of 56% and fledging success at 93% (1 Cuthbert, R.J. (2005). Breeding biology, chick growth and provisioning of Great Shearwaters (Puffinus gravis) at Gough Island, South Atlantic Ocean. Emu. 105(4): 305–310. Close ), while subsequent research on same island has recorded consistently high rates of burrow occupancy over four seasons: 68·7% (range 65–77%), with hatching success, fledging success and overall breeding success averaging 56·9%, 81·7% and 43·2%, respectively, and for fledging, success was high in two seasons (93–96%) and lower (56%) in one (28 Cuthbert, R.J., Louw, H., Lurling, J., Parker, G., Rexer-Huber, K., Sommer, E., Visser, P. and Ryan, P.G. (2013). Low burrow occupancy and breeding success of burrowing petrels at Gough Island: a consequence of mouse predation. Bird Conservation International. 23(2): 113–124. Close ). No further information.

Not globally threatened (Least Concern). Abundant, with enormous total population, perhaps numbering as many as 15,000,000 individuals (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ); minimum 5,000,000 breeding pairs at Tristan da Cunha (of which c. 2,000,000–3,000,000 pairs on Nightingale I and 2,000,000 pairs on Inaccessible I, where numbers are speculated to have increased over last half-century) (29 Ryan, P. G., and C. L. Moloney (2000). The status of Spectacled Petrels Procellaria conspicillata and other seabirds at Inaccessible Island. Marine Ornithology 28(2):93–100. Close , 4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ), 600,000–3,000,000 pairs at Gough I (1970), where numbers more recently (2000/01) estimated at 980,000 pairs (30 Cuthbert, R. (2004). Breeding biology of the Atlantic Petrel, Pterodroma incerta, and a population estimate of this and other burrowing petrels on Gough Island, South Atlantic Ocean. Emu. 104(3): 221–228. Close ), and small numbers (50–100 pairs) (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ) on Kidney I in Falklands. Highly restricted breeding range, with only four sites known. A few thousand adults and c. 40,000–50,000 chicks taken annually from uninhabited Nightingale I by Tristan islanders (1973–1974), as well as 15,000 eggs in 1950 (4 Brooke, M. (2004). Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. Close ); such levels of exploitation could lead to collapse of population, and establishment of quota system recommended, to allow for rational exploitation. Research required into impact of harvesting, importance of other causes of mortality and population dynamics, in order to determine maximum sustainable levels of exploitation. Some are taken as bycatch by longline fishery for hake Merluccius spp. in shelf waters off South Africa (31 Barnes, K.N., Ryan, P.G. and Boix-Hinzen, C. (1997). The impact of the hake Merluccius spp. longline fishery off South Africa on procellariiform seabirds. Biological Conservation. 82(2): 227–234. Close ), by gillnet fisheries off NE Canada (32 Benjamins, S., Kulka, D.W. and Lawson, J. (2008). Incidental catch of seabirds in Newfoundland and Labrador gillnet fisheries, 2001–2003. Endangered Species Res. 5(2–3): 149–160. Close ), and the species is also known to attend longline fisheries off Brazil (3 Olmos, F. (1997). Seabirds attending bottom long-line fishing off southeastern Brazil. Ibis. 139(4): 685–691. Close ), Uruguay (33 Jiménez, S., A. Domingo, A. Marquez, M. Abreu, A. D’Anatro, and A. Pereira (2009). Interactions of long-line fishing with seabirds in the southwestern Atlantic Ocean, with a focus on White-capped Albatrosses (Thalassarche steadi). Emu 109(4):321–326. Close ) and Argentina (34 Gandini, P.A. and Seco Pon, J.P. (2007). Seabird assemblages attending longline vessels in the Argentinean Economic Exclusive Zone. Orn. Neotropical. 18(4): 553–561. Close ), and therefore to be at risk there. Ingestion of plastics (35 Pierce, K.E., Harris, R.J., Larned, L.S. and Pokras, M.A. (2004). Obstruction and starvation associated with plastic ingestion in a Northern Gannet Morus bassanus and a Greater Shearwater Puffinus gravis. Marine Orn.. 32(2): 187–189. Close ) and heavy metals (36 Barbieri, E., Borges Garcia, A., Andrade Passos, E., Aragão, K.A.S. and Hora Alves, J.P. (2007). Heavy metal concentration in tissues of Puffinus gravis sampled on the Brazilian coast. Rev. Bras. Orn. 15(1): 69–72. Close ) are additional hazards at sea.