Puffin us gravis 619

Puffin us gravis Great COLOUR PLATE FACING PAGE 592

Procellaria gravis O'Reilly, 1818, Greenland Adjacent Seas North-west Passage: 140, pI. 12, fig. 1 - Cape Farewell and Staten Hook to Newfoundland.

The specific name, gravis, means 'heavy'.

MONOTYPIC

FIELD IDENTIFICATION Length 43-51 cm; wing­ edea, Streaked Shearwater C. leucomelas and Grey Petrel span 100-118 cm. Large shearwater, with long slender dark Procellaria cinerea by dark bill, dark clear-cut cap, dark diag­ bill; similar in shape to Flesh-footed Shearwater P. cameipes onal bars across white underwing and brown patch on belly. but slightly larger; dark greyish-brown above, with distinctive From Pink-footed Shearwater Puffin us creatopus by dark clear-cut dark cap, narrow white collar and white horseshoe bill, dark clear-cut cap and white band across upper tail-cov­ on upper tail-coverts. Dark belly patch on mainly white erts. From Buller's Shearwater P. bulleri by clear-cut darker underbody, and white collar, diagnostic among . cap, white band on upper tail-coverts, brown patch on belly Sexes alike. No seasonal variation. and absence of dark M-pattern across upperwings and rump. DESCRIPTION Forehead, crown, nape, upper From light-phase Wedge-tailed Shearwater P. pacificus by cheeks and ear-coverts, dark brown, forming blackish cap clear-cut cap, white band on upper tail-coverts, shorter tail extending just below eye level where sharply demarcated from and brown patch on belly. From Barau's Petrel Pterodroma white lower cheeks, chin, throat and foreneck. White of fore­ baraui and Juan Fernandez Petrel P. extema by larger size, neck extends behind cap and across nape to form conspicuous longer and more slender bill, dark forehead, different un­ white collar separating cap from hindneck and saddle, some­ derwing pattern (noticeably broader dark trailing-edge, dark times interrupted centrally by narrow grey-brown extension bars across wing-pit), dark under tail-coverts and brown patch of hindneck. Hindneck, greyish brown; mantle, back, rump, on belly; also by flight and jizz, typical of shearwaters. short upper tail-coverts and scapulars, dark greyish-brown to Flight rapid and powerful with wings held stiff and blackish, with narrow paler greyish-brown to whitish fringes straight; usually series of fairly rapid wing-beats inter­ imparting scaled appearance to saddle; distal upper tail-coverts spersed with glides low over water and banking. Often highly broadly tipped white, forming prominent horseshoe-mark gregarious at sea, especially off breeding grounds before above tail. Tail, blackish. Upperwing: inner wing-coverts, migration (Rowan 1952), on wintering areas in northern dark greyish-brown with fine pale fringes; contrast with hemisphere and off e. S. America, where often join flocks of blackish primaries, primary coverts and secondaries; lesser many other (Brown et al. 1975a). Mostly solitary in s. coverts sometimes appear darker than surrounding coverts, Indian Ocean O-c. Stahl). Often follow shoals of and showing as ill-defined dark bar across innerwing from carpal groups of cetaceans. Food obtained by plunge-diving from 6- joint to longest scapulars and, with blackish outerwing, forms 10 m above water, or pursuit-diving from surface. Attend subtle dark M across upperwing. Underbody, white except trawlers and fishing vessels and regularly follow ships. In s. for short greyish-brown patch on upper sides of neck, black­ Indian Ocean, ship-followers almost invariably stay further ish-brown belly patch, greyish-brown smudges on rear flanks, behind vessel than other species O.-c. Stahl). and blackish-brown under tail-coverts which combine with blackish undersides of rectrices to form dark rear-end. Un­ HABITAT Marine, in offshore and pelagic waters; rare derwing: undersides of remiges, black, showing as narrow inshore or in narrow seas (Cooke & Mills 1972; Brown et al. dark trailing-edge and tip sharply demarcated from white of 1975a,b; Liversidge & Le Gras 1981; BWP). In s. hemisphere, lining. Lining mostly white, with narrow black leading edge mainly over s. subtropical and subantarctic waters; only from elbow to base of outermost primary, broadest along pri­ occasionally S of Antarctic Convergence (Watson 1971; mary coverts, with thin black streaks radiating across white Tickell & Woods 1972; Harris 1982; Thurston 1982). In s. ground of lesser and outer median primary-coverts. On in­ Indian Ocean, mostly near Subtropical Convergence O.-c. nerwing, thin black streaks on lesser coverts and bold black Stahl). In S. Atlantic, over waters with sea surface-tempera­ tips to subhumerals form pronounced diagonal bar from tures, 6-23 °C, in summer; greatest densities over waters of carpal joint to posterior base of wing; in front of this, bold 9-16 °C; concentrations over upwellings and at boundaries of black tips to subhumeral coverts form second diagonal bar cool currents and warm coastal water (Cooke & Mills 1972; across wing-pit; both bars often broken; small black spots on Brown et al. 1975a). On migration, cross Tropical Zone ra­ wing-pit in front of second bar. Iris, brown. Bill, long and pidly without stopping (BWP). Spend non-breeding season in slender, with tubed nostrils inconspicuous over basal quarter n. Atlantic Ocean, mostly in Boreal and low Arctic waters of upper mandible; dark blackish-brown, with base of lower (Brown et al. 1975b; Powers 1983), including those with scat­ mandible, grey. Legs and feet, pale flesh to pink, except for tered icebergs, but do not reach pack-ice (BWP). Off e. North brown to black outer tarsus and toe. America, greatest densities over shelf waters (Powers 1983). SIMILAR SPECIES Readily distinguished from In Tristan Grp, breed up to 400 m asl, wherever soil deep other large shearwaters with bicoloured plumage by clear-cut enough to excavate burrows; greatest densities in uniform dark cap, and diagnostic prominent white collar and dark tussock grassland and in Phylica woodland (Rowan 1952; belly-patch (the latter surprisingly difficult to see in field). Fraser et al. 1988). Distinguished from Cory's Shearwater Calonectris diom- Away from land, fly at lowest levels; approach land at 620 heights of few metres to 300 m and soar to 450 m (Rowan I. (600 000-3 million pairs; Elliott 1970); also Falkland Is (lOOs 1952). Rest and feed in rafts on surface; make shallow dives to pairs; Croxall et al. 1984). at least 2 m depth (Brown et al. 1978). MOVEMENTS Transequatorial migrant to N. Atlantic DISTRIBUTION Mostly S. Atlantic and sw. Indian from breeding grounds in S. Atlantic. Ocean during breeding season (Sept.-May), breeding only on DEPARTURE Departure from colonies: adults S. Atlantic islands of Grp (Nightingale I., mid-April, juveniles May (Rowan 1952). Inaccessible I.), Gough I. and Falkland Is (single breeding pair NON-BREEDING First wave of migrants (probably recorded on Kidney I. ; BWP); migrate to N. Atlantic outside adults) arrives w. central N. Atlantic, late May; on Georges breeding season. Vagrant to A'asia. Bank, June (Voous & Wattel1963; Powers 1983), which sug­ During all or part of breeding season: S. Atlantic mostly gests migration through central Atlantic and subsequent W between 38-52°S (Tickell & Woods 1972), further S to Le and N dispersal. Adults from Inaccessible I. (Tristan group) Maire Channel (c . 55°S) off e. S. America (Watson 1971); recovered Newfoundland in July (Fraser et al. 1988). Spread to occasionally N to 32°S (Thurston 1982) and S of Antarctic ne. Atlantic by Aug. (Rowan 1952). Second wave of migration Convergence to near S. Georgia and n . S. Sandwich Is (probably juveniles and young immatures) observed on (Watson 1971). Regular but uncommon off w. S. Africa and e. passage in June in E. Sargasso Sea (c. 1rN, 53°W; Voous & Cape (Liversidge 1959; Brooke & Sinclair 1978; Liversidge & Wattel 1963) and off Senegal and Guinea (Voous & Wattel Le Gras 1981) and S of Africa between 39-54°S (van Oordt & 1963), possibly including from se. American and S. Kruijt 1954; Harris 1982). Abundant off Brazil and Argentina African waters. A few birds winter off S. Africa and in sw. (Blake 1977). Sw. Indian Ocean: small numbers E to at least Indian Ocean. S migration probably on broad front across 65°E, mostly between 39- 45°S, occasional N to 34°S (Stahl whole ocean (Rowan 1952; Bourne 1970). 1987; J.-G Stahl) and shelf round Iles Crozet (Stahl et al. RETURN Most adults return to breeding grounds 1984). second half of Sept. (Rowan 1952; Fraser et al. 1988). Non­ In N. Atlantic mainly May-Nov. Main wintering areas, breeding birds remain numerous in nw. and ne. Atlantic until nw. Atlantic including shelf off e. from 40- late Oct.-mid-Nov. (Voous & Wattel 1963; BWP). 67°N (Powers 1983; Brown et al. 1975b); central N. Atlantic BREEDING In s. summer, dispersed across S. At- from 40-66°N (Voous & Wattel1963); oceanic waters offw. lantic with concentrations off S. Africa, Oct.-Jan. Non­ Europe between Iberian Pen. and Rockall Bank (BWP). breeding birds in moult, Jan.-Feb., in Le Maire Channel off Accidental N. Pacific: one record, California in Feb. Tierra del Fuego (Watson 1971) and shelf ofIles Crozet (Stahl (Roberson 1980). et al. 1984). AUST. Single birds, possibly same individual, SW of Robe (37/ 138; 37/ 139), Jan., Feb. 1989 (D.W . Eades; N.G . PLUMAGES Cheshire). ADULT Definitive basic. Age of first breeding NZ Sightings Wand NW of Kermadec Is in Dec.- unknown. HEAD AND NECK. Top of head to below eye, dark Jan., and in Cook Str. in July Oenkins 1968) have been rejected brown (121), contrasting with white chin, throat and hind­ (Bourne 1971). neck to form dark cap. Some white mottling below eye. BREEDING Breed in great numbers in Tristan da UPPERPARTS. Mantle, pale grey-brown (c119C). Back, rump, Cunha group (5 million + pairs; Williams 1984) and at Gough most scapulars and lateral upper tail-coverts, dark brown (121) Puffinus gravis 621 with pale-brown to off-white scalloping. Feathers, dark ported moulting at sea in Aug. (Voous 1970). brown (121) with pale-brown (119C-119D) fringes, narrower on edges. Longer scapulars, blackish brown (119) with white MEASUREMENTS Full-grown, skins (BWP). Longest­ fringes, narrowest on edges. Longer upper tail-coverts, white. winged male and female in this sample are fledgelings; newly TAIL, black-brown (119) with narrow white tips lost with wear. fledged birds with remnant down may have longer wings than UPPERWING. Outer webs, tips and inner edge of inner webs of adults (Elliott 1957). primaries, brown-black (119); rest of primaries, white. Secondaries and secondary coverts, grey (84) with white MALES FEMALES fringes and proximal two-thirds of inner web. Other up­ perwing feathers, dark brown (121) with pale-brown (119C- WING 332 (8.61; 318-348; 10) 318 (11.3; 301-334; 6) 119D) to off-white fringes, narrowest on edges. UNDERPARTS, TAIL 117 (3 .66; 113-126; 10) 113 (4.37; 109-120; 8) mostly white with brown (119C) patch on belly; extent varies. BILL 46.0 (1.71; 43-50; 12) 44.0 (1.14; 43-47; 8) Sides of breast, grey-brown (c119C). Feathers oflower flanks TARSUS 59.8 (1.48; 58-63; 12) 59.0 (1.20; 57-60; 8) and under tail-coverts, grey-brown (119B but greyer) with TOE 71.6 (2.67; 68-77; 10) 69.4 (1.34; 68-71; 5) pale-brown (119D) to white tips. Other flank-feathers, white with large brown (119B) mark near tip of outer web. Axillar­ ies, white with dark-brown (c119A) tips. UNDERWING. Pre­ Other measurements in Hagen (1952), Swales (1965), dominantly white with narrow dark trailing-edge, narrow Brown et al. (1981). dark leading-edge, and broken diagonal bars from tips of ter­ tials to carpal joint. Visible parts of remiges, brownish grey. WEIGHTS Breeding adults at Tristan da Cunha: 834 Marginal coverts, dark brown (c119a) fringed white. Outer­ (59.1; 715-950; 14; Hagen 1952). Sex difference negligible. most primary greater, primary median and primary lesser under wing-coverts, dark brown (c119A) with concealed STRUCTURE Eleven primaries, p11 minute, plO lon­ white bases to inner webs. Remaining under wing-coverts, gest, p9 2-9, p8-16-26, p7 31-50, p6 50-75, p5 84-88, p4 white; subhumerals and inner secondary median under wing­ 111-117, p3 138-160, p2 161-176, pl162-193; 20-22 secon­ coverts have grey-brown (greyish 119A) rosethorns; primary daries (Mayaud 1949-50). Tail strongly rounded; t1 c. 25-30 lesser under wing-coverts have dark-brown shaft-streaks; and longer than t6. Bill powerful with strong terminal hook. Nasal inner secondary lesser under wing-coverts have dark-brown tubes one-fifth to one-quarter length of bill; oval nostrils (c119A) tips. separated by broad septum; point forwards and upwards. JUVENILE Fresh plumage has grey bloom (Palmer Tarsus stout, laterally compressed. Middle and outer toes 1962). about equal, inner c. 85-90%, hind toe rudimentary. ABERRANT PLUMAGES Complete and partial albinism reported (Elliott 1957; Richardson 1984; Lee & GEOGRAPHICAL VARIATION None. Bourne (in Grant 1986). Palmer 1962) suggested P. gravis, P. cameipes and P. creatopus form circumpolar superspecies. BARE PARTS Based on Elliott (1957), Murphy, DIR BWP. ADULT, JUVENILE Iris, dark brown (-) . Bill, dark REFERENCES horn-grey (c88); lower part of lower mandible, blue-grey; Blake, E.R. 1977. Manual of Neotmpical Birds. 1. whitish spot on maxillary unguis. Outer toe and outer side of Bourne, W .R.P. 1970. Sea Swallow 20: 50. tarsus, black (-). Rest of feet and legs, usually flesh, ranging Bourne, W.R.P. 1971. Notornis 18: 222. Brooke, R.K., & j.C. Sinclair. 1978. Cormomnt 4: 10-17. from white to deep pink (especially in juveniles). Brown, R.G.B., et al. 1975a. Ibis 117: 339-56. Brown, R.G.B., et al. 1975b. Atlas of Eastern Canadian Seabirds. MOULTS Based on Stresemann & Stresemann (1970) Brown, R.G.B., et al. 1978. Condor 80: 123-5. except where stated. Brown, R.G.B., et al. 1981. Ibis 123: 19-30. ADULT POST-BREEDING Pre-basic. Complete, Cooke, F., & E.L. Mills. 1972. Ibis 114: 245-51. in winter quarters; wing-moult between end of May and mid­ Croxall, J.P., et al. 1984. ICBP Tech. Publ. 2: 271-91. Aug. Primaries outwards; as many as six may grow at one time; Elliott, C.C.H. 1970. Ostrich Suppl. 8: 385-96. duration 90 days; estimated growth rate of primaries, five Elliott, H.F.I. 1957. Ibis 99: 545-86. Fraser, M.W., et al. 1988. Cormorant 16: 7-23. mm/ day. Secondaries moult at same time as primaries, in 4 Hagen, Y. 1952. Results Norw. scient. Exped. Tristan da Cunha 20: groups; sl-s4, s5-s12/ 13/ 14 and s19/ 20-s21/ 22 inwards, and 1-248. s18/ 19-s13/ 12 outwards (Mayaud 1949/ 50). Never flightless Harris, M.P. 1982. Br. Antarct. Surv. Bull. 55: 105-109. during moult (contra Meinertzhagen 1956), although moult­ Jenkins, ).A.F. 1968. Notornis 15: 214-215. ing birds can have difficulty taking off (V oous 1970). In early Lee, D.S., & G.S. Grant. 1986. Wilson Bull. 98: 491-508. stages of moult, white wing-bar formed when loss of coverts Liversidge, R., & G.M. Le Gras. 1981. Pp. 149-67. In: Proc. Symp. exposes white bases of secondaries and greater primary Birds Sea Shore. coverts. Body and wings moult at same time; tail somewhat Liversidge, R. 1959. Ostrich Suppl. 3: 47-67. later. Mayaud, N. 1949-50. Alauda 17-18: 144-45,222-33. POST-JUVENILE Partial; body-plumage replaced Meinertzhagen, R.M. 1956. Bull. Br. Orn. Club 76: 17-22. Palmer, R.S. 1962. Handbook of North American Birds. 1. in July-Aug. of first year (Stresemann & Stresemann Powers, K.D. 1983. Pelagic Dist. Mar. Birds ne. US. NOAA Tech. 1970). Memo. NMFS-FjNEC-27. SUBSEQUENT PRE-BASIC MOULTS Second- Richardson, M.E. 1984. Cormomnt 12: 121-99. year birds growing p1-p4 reported off coast Tierra del Fuego Roberson, D. 1980. Rare Birds of the West Coast of North Amer­ in Jan. (Watson 1971). Non-breeders of unknown age re- ica. 622 Procellariidae

Rowan, M.K 1952. Ibis 94: 97-121. Tiekell, W .L.N., & R.W. Woods. 1972. Br. Antarct. Sum Bul!. 31: Stahl, J-c. 1987. TAAF MR. Rap. Camp. iz la mer 84-01: 175- 63-84. 190. van Oordt, G.]., & J.P. Kruijt. 1954. Ardea 42: 245-80. Stahl, ]-c., et a!. 1984. Gerfaut 74: 39-46. Voous, KH. 1970. Ardea 58: 265-6. Stresemann, E., & V. Stresemann.1970. ]. Om., Lpz., 111: 378-93. loous, KH., & J. Watte!. 1963. Ardea 51 : 143-57. Swales, M.K. 1965. Ibis 107: 215-29. Watson, G.E. 1971. Auk 88: 440-2. Thurston, M.H. 1982. Br. Antarct. Sum Bull. 55: 77-103. Williams, A.]. 1984. ICBP Tech. Pub!. 2: 627-35.

Puffin us grise us COLOUR PLATE FACING PAGE 656

Procellaria grisea Gmelin, 1789, Syst. Nat. 1:564; based on 'Grey Petrel' of Latham, 1785, Gen. Syn. Birds 3: 399 - between 35° and 500 S = New Zealand, restricted by Mathews, 1912, Birds Aust. 2: 95.

The specific name is medieval Latin for 'grey', referring to the colour of the plumage.

OTHER ENGLISH NAMES King or New Zealand Muttonbird, Sombre Petrel or Shearwater.

MONOTYPIC

FIELD IDENTIFICATION Length 40-46 cm; wing­ SIMILAR SPECIES Short-tailed Shearwater, span 94-105 cm; weight 650-950 g. Large solid-bodied always smaller though not always apparent; bill, shorter, (one shearwater, closely resembling slightly smaller Short-tailed of the most reliable features). Underwing pattern: often have Shearwater Puffinus tenuirostris. Long slender bill, slender pale feathers restricted to centre, appearing as white streak flat-crowned head and longish neck. Slim wings, not so long (Sooty generally has larger area of white in area of primary or broad as other large shearwaters. Tail, short and rounded; coverts) but some can have as much white on underwing as feet extend slightly beyond tip of tail in flight. Cruciform average Sooty; in close views, most do not have streaks shape in flight; faintly recalls large fluttering-type shearwater through whiter parts of underwings. Identification should not distinct from other large shearwaters that soar and flap wings be made solely on underwing pattern, but often useful when less (except for P. tenuirostris). Entirely dark brown-grey ex­ flocks of either species seen, as individual variation can be cept broad pale streak down centre of underwing. Sexes alike. assessed. In close views, more abrupt profile of head (Sooty Seasonal variation in colour, rapidly wearing from dark tend to have flatter-crowned appearance and less of a fore­ brown-grey to brown. Fledgelings generally inseparable; in head). Harrison (1987) suggested that Short-tailed Shearwat­ Apr. and May, distinguished by fresh blackish plumage (when ers have paler throats and darker caps, imparting more adults worn, brown) and larger, more silvery (not white) un­ hooded appearance. However, throat-colour varies, not all derwing panel. having paler throats, and should not be relied on. In Bass Str., DESCRIPTION ADULT. Head, upperbody, up- Jan.-Aug., Short-tailed Shearwaters never show moult of perwing and tail, uniform dark brown-grey; browner when remiges (Sooty Shearwaters, assumed to be non-breeding, plumage worn. Underbody, slightly paler than upperparts but often in heavy moult, especially of remiges). Wedge-tailed still mid- to dark-grey. Often appears all dark at sea apart from Shearwater P. pacificus has very different structure with underwing. Underwing varies but always has dark grey­ smaller head and body, long slender wedge-shaped tail and brown leading-edge to inner wing and slightly darker subhu­ long broad wings, held well forward and bowed with pro­ merals. Primary coverts, apart from leading-edge, vary: all­ nounced carpal bend. Also all-dark underwing and pale feet white; white streaked with blackish shafts; white in centre, that do not extend past tip of tail. Flight, lazy and buoyant, very heavily streaked blackish; rarely, all-grey, sometimes without bursts of rapid stiff-winged fluttering of Sooty. Flesh­ streaked blackish. Most have more white in area of primary footed Shearwater P. carneipes, with heavier paler bill and coverts than do Short-tailed Shearwaters. Secondary coverts, broader wings. Underwing, dark but can appear silvery in generally grey except for median coverts, which usually white bright sunlight. Pale feet do not protrude beyond tip of tail. centrally, often streaked blackish. Often appears all black to Flight, more leisurely with less flapping. Christmas brownish in field with paler, often whitish central underwing. Shearwater P. nativitatis, markedly smaller, with broader In strong sunlight, reflection can make underwing appear wings and longer tail. Under wing-coverts, dark; feet, dark, paler, silvery. Bill, long and slender; nostrils raised only not extending beyond tip of tail. Great-winged Petrel Ptero­ slightly over base of upper mandible; culminicorn and nos­ droma macroptera appears large-headed and bull-necked, trils, black; rest, dark brownish grey; usually appears blackish with stubby black bill and high forehead. Face, usually grey; at sea; in strong light, can appear paler, but never as pale as underwing, dark. Long slender wings held well forward and Flesh-footed Shearwater P. carneipes, or Wedge-tailed swept back from carpal joint. Shearwater P. pacificus. Iris, dark brown. Legs and feet, black­ Abundant in s. oceans in summer, especially round s. NZ. ish on outside of tarsus and outer toe; inside of tarsus and rest Singly or in small flocks but usually highly gregarious, often of toes and webs, flesh-pink. feeding in huge flocks or gathering in rafts of thousands off