VOL. 13 (2) JUNE 1989 39

AUSTRALIAN WATCHER 1989, 13, 39-43

Barau's Petrel Pterodroma baraui, a New Species for Australia

by MIKE CARTER', TIM REID2 and PETER LANSLEY3

130 Canadian Bay Road, Mt Eliza, Victoria 3930 2Flat 2/61 Fawkner Street, St Kilda, Victoria 3182 3Flat Tl/99 Epsom Road, Ascot Vale, Victoria 3032

Summary Barau's Petrel Pterodroma baraui can now be added to the Australian Jist. An observation by a group of observers in Victorian waters in February 1987 is documented. This occurrence is discussed in relation to the Indian Ocean distribution of this species and to subsequent observations off Western Australia. The observation On 15 February 1987 at 0945 h (GMT + 11 hours), a Barau's Petrel Pterodroma baraui was observed at sea off western Victoria. All sixteen participants in a group excursion aboard a 13.0 m long fishing boat saw the bird as it came to within 50 m of the stationary vessel lying at 38 "32'S, 141 "1.7 'E. This is some 12.5 nautical miles south-west of Cape Bridgewater and towards the edge of the continental shelf at a water depth of 155 m (85 fathoms). As there was a reasonable concentration of at this location, we had stopped the boat to determine the abundance and range of species present. We attracted the birds to the boat by berleying with scraps and fresh meat fat doused in cod liver oil. The congregation consisted of c. 25 Black-browed Albatrosses Diomedea melanophris, c. 25 Yellow-nosed Albatrosses D. chlororhynchos, two Shy Albatrosses D. cauta, one Great-winged Petrel Pterodroma macroptera, one Fairy Prion Pachyptila turtur, three Flesh-footed Shearwaters Pujjinus carneipes, c. 10 Short-tailed Shearwaters P. tenuirostris, two Wilson's Storm-Petrels Oceanites oceanicus, one Grey-backed Storm-Petrel Garrodia nereis and c. 50 White-faced Storm-Petrels Pelagodroma marina. It was presumably this gathering of feeding birds which caused the Barau's Petrel to pass close to our boat, diverging slightly from its easterly heading. The petrel was first sighted whilst still some considerable distance off as it approached the boat. It immediately excited attention. Viewed head-on its size and white forehead suggested White-headed Petrel Pterodroma lessonii. However, once its black and white, Black-winged Petrel Pterodroma nigripennis type ventral pattern was visible, identification became problematical. Because of its size and general appearance, a petrel of the Juan Fernandez!White"necked Pterodroma externa!cervicalis complex was suspected but the bold under-wing pattern precluded these forms. The possibility of it being an aberrant Pterodroma inexpectata, a normally dark-bellied species, was dismissed by the detail of the underprimary pattern, size, and general colour of the upperparts. The bird passed without pausing. After writing notes, using Harrison (1983), we determined the bird to be a Barau's Petrel, an Indian Ocean species for which prior occurrence in Australian waters had not been established. At the time of the observation, the weather was fine .Jith part cloud cover. Although not sunny the light was good, providing excellent viewing conditions. The nearby Cape AUSTRALIAN 40 CARTER, REID & LANSLEY BIRD WATCHER

Nelson lighthouse reported the wind at 0600 h and 0900 h to be from the south-south­ east at 15 knots. This produced a moderate sea on a low swell. Later, during the afternoon, the wind backed to the south-east and strengthened to 20 knots.

Description The petrel was reminiscent of a White-necked Petrel Pterodroma (e.xteT7Ul) cervicalis but was rather more robust. This impression was confirmed for MJC when just thirteen days later he saw a White-necked Petrel at sea off Wollongong, New South Wales. The flight of the Barau's Petrel was sedate, lazy, straight and close to the sea. The forehead and face from the bill to the eyes was white, the crown blackish and the remainder of the upperparts a fairly uniform mid to dark grey. TR considered that the outer primaries, lower back and tail were a shade darker than the remainder of the upperparts. PL considered that there was an inconspicuous darker 'M' marking across the upper-wings and back. MJC was aware of some minor variation in shade but did not discern this as forming any distinct, easily definable, pattern. There was no white collar around the hind neck. TR thought that the mantle feathers were faintly patterned, possibly with paler edgings. The whole of the underside of the head, neck and body was white, merging with the grey upperparts along the side of the head, neck and flanks. There was no dark pectoral crescent like that of the White-necked Petrel. The undersides of the wings were mainly white with a bold pattern of black similar to that of the Black-winged Petrel Pterodroma nigripennis. That is, a broad black band extending along the leading edge of the wing from the base of the primaries to the carpal and then passing diagonally across the inner wing towards the armpit. The whole of the underside of the primaries and secondaries exposed beyond the under-wing coverts were also black.

lllustrations The drawing by Jeff Davies, Plate 15, is included for illustration purposes only and is not meant to be a picture of the bird seen. Jeffs recollections of the bird are embodied in the drawing, with detail embellished by reference to photographs in Jadin & Billiet (1979) and Jouanin & Gill (1967). Murray Grant also saw the bird. His paintings, Plate 16 was done from memory as influenced by reference to Harrison (1983, 1987). No other reference was consulted. The authors consider that these illustrations are good representations of the bird seen.

Identification The bird we saw closely matched the illustrations and description of Barau's Petrel given by Harrison (1983). Identification to this species was confirmed by reference to Harrison (1987), Thck & Heinzel (1978), Jouanin & Gill (1967) and Jadin & Billiet (1979). It is interesting to note that for his later book, Harrison had modified his description of the 'M' mark across the upper-wings from 'slight' to 'distinct'. The photograph by A.B. van den Berg on page 59 of Harrison (1987), a dorsal view, does show a distinct 'M'. Harrison's altered opinion is reflected in his drawings and painting of this species in the same volume. We do not regard such differences as significant because the intensity of the 'M' mark varies with moult and plumage condition in the closely related White-necked Petrel and other birds with similarly patterned upperparts such as Buller's Shearwater Puffinus bulleri (pers. obs.). Moreover, van den Berg's photograph was taken in June, after the breeding season, when fresh juveniles, or adults in worn plumage, are to be expected. VOL. 13 (2) JUNE 1989 Barau's Petrel, New Species for Australia 41

A Barau's Petrel Plate 15 Drawing: Jeff Davies AUSTRALIAN 42 CARTER, REID & LANSLEY BIRD WATCHER

Barau's Petrel: ventral and dorsal views Plate 16 Paintings: Murray Grant

World-wide, there are another fifteen members of the genus Pterodroma which bear a superficial resemblance to Barau's Petrel. However, none has the combination of features described above. The following are excluded by size (all being too small), as well as plumage characters: Cook's Petrel P. cooki, Masatierra Petrel P. (cooki) defilippiana, Stejneger's Petrel P. longirostris, Pycroft's Petrel P. (longirostris) pycrofti, Gould's Petrel P. leucoptera, Collared Petrel P. (leucoptera) brevipes, Bonin Petrel P. hypoleuca, Chatham Island Petrel P. a.xillaris and Black-winged Petrel P. nigripennis. Mottled Petrel P. inexpectata is eliminated by jizz, the absence of black on the belly and because the undersides of the primaries are mainly white whereas in our bird they were largely black. Hawaiian Petrel P. phaeopygia and Black-capped Petrel P. hasitata can be discounted because those species have black caps and some white on the rump. Bermuda Petrel P. cahow is not a contender because that species is darker dorsally and has dark patches on the sides of the breast. The Juan Fernandez Petrel P. extema is eliminated because that species has an almost completely white under-wing. Its close relative, the White-necked Petrel P. (externa) cervicalis, has a rather bolder but still narrow black diagonal mark on the under-wing, has a white cervical collar and the background colour of the upperparts is a paler grey. VOL. 13 (2) JUNE 1989 Barau's Petrel, New Species for Australia 43

Discussion Barau's Petrel is a little-known Indian Ocean species first described by Jouanin in 1964. It breeds only on Reunion and Rodriguez Islands between November and April. The world population is numbered in thousands (Brooke 1978; C.J. Feare in Croxall, Evans & Schreiber 1984; Jadin ,& Billiet 1979; Jouanin & Gill 1967). The distribution of Barau's Petrel when at sea is not well known. Harrison (1983) postulated an easterly dispersal in the subtropical convergence zone south of about 20 °S. Recent reports attest to the wide range of this species and to its occurrence in the eastern Indian Ocean. P. Meeth reported sighting five birds in August 1986, all in tropical waters in the general vicinity of Cocos (Keeling) Islands (Chapman & Cheshire 1987). One bird was seen as far north as 7 ~9 'S. On 1 July 1984 one was seen south-west of Enggano Island, Sumatra (van Marie & Voous 1988). In the same region but even farther east in the vicinity of Christmas Island, Dunlop, Cheshire & Wooller (in press) reported two birds in October 1987. Eades (in press) logged a total of 24 Barau's Petrels in a twenty-six day cruise from Fremantle to Cape Town via lle Amsterdam in March/April1987. Three of these were in the south-eastern Indian Ocean, one being in Australian waters at 31°56 'S, 111°55 'E. His most southerly observation was at 41 OZ2 'S. In view of this growing evidence that the eastern Indian Ocean is within the normal pelagic range of this species, it is not surprising that the occasional Barau's Petrel could continue its easterly course thus reaching Victorian waters.

Acknowledgements We wish to acknowledge the assistance provided by the other observers present, these being: Wallie Coles, Mike Conner, Jeff Davies, Geoff Duggan, Bob Dunstan, Murray Grant, Frank Harrap, Garry John, Lyle Smith, Tom Smith, Jon Starks, Jeff Swainson and Bill Watson. Jeff Davies and Murray Grant kindly provided the illustrations. We also thank Neil Cheshire and David Eades for providing advice and reference material.

References Brooke, M.de L. (1978), 'Inland observations of Barau's Petrel Pterodroma baraui on Reunion', Bull. Br. Omithol. Club 98, 90-95. Chapman, S.E. & Cheshire, N.G. (1987), 'Notes on seabird reports received 1986', Sea Swallow 36, 32-45. Croxall, J.P., Evans, P.G.H. & Schreiber, R.W. (Eds) (1984), 'Seabird status and conservation in the Tropical Indian Ocean', in Status and Conservation of the J#Jrld's , ICBP Technical Publication no. 2, Cambridge. Dunlop, J.N., Cheshire, N.G. & Wooller, R.D. (in press), 'Observations on the marine distribution of tropicbirds, Sooty and Bridled Terns, and gadfly petrels from the eastern Indian Ocean', Rec. ~st. Aust. Mus. Eades, D.W. (in press), 'Seabirds observed in the southern Indian Ocean during March-April, 1987 - preliminary results', Australasian Seabird Group News/. Harrison, P. (1983), Seabirds: An Identification Guide, Reed, Sydney. -- (1987), Seabirds of the World, A Photographic Guide, Christopher Helm, Bromley, Kent. Jadin, B. & Billiet, F. (1979), 'Observations ornithologiques a Ia Reunion', Le Gerfaut 69, 339-352. Jouanin, C. & Gill, F.B. (1967), 'Recherche du Petrel de Barau, Pterodroma baraui', L'Oiseau et Ia R.F.O. 37, l-19. Thck, G.S. & Heinzel, H. (1978), A Field Guide to the Seabirds ofBritain and the »brld, Collins, London. London. van Marie, J.G. & Voous, K.H. (1988), The Birds of Sumatra, Brit. Ornithologists Union Checklist no. 10, Tring, Herts.

Received 4 October 1988 •