NOTORNIS Journal of the Ornithological Society of New Zealand Volume 32 Part 3 September 1985 OFFICERS 1985-86 President - B. BROWN, 20 Redrnount Place, Red Hill, Papakura Vice-president - D. E. Crockett, 21 McMillan Ave., Kamo, Whangarei Editor - B. D. HEATHER, 10 Jocelyn Crescent, Silverstream Treasurer - D. F. BOOTH, P.O. Box 35357, Browns Bay, Auckland 10 Secretary - R. S. SLACK, c/o P.O., Pauatahanui, Wellington Council Members: BEN D. BELL, Zoology Dept, Victoria University, Private Bag, Well~ngton BRIAN D. BELL, 9 Ferry Road, Seatoun, Wellington P. C. BULL, l3lA Waterloo Road, Lower Hutt P. D. GAZE, Ecology Division, Private Bag, Nelson B. J. GILL, Auckland Institute & Museum, Private Bag, Auckland J. HAWKINS, 772 Atawhai Drive, Nelson P. M. SAGAR, 38A Yardley Street, Christchurch 4 Conveners and Organisers: Rare Birds Committee: Secretary, J. F. M. FENNELL, 224 Horndon Street, Dqrfield, Canterbury Beach Patrol: R. G. POWLESLAND, Wildlife Service, Dept. of Internal Affairs, Private Bag, Wellington Librarian: A. J. GOODWIN, R.D. 1, Clevedon Nest Records: H. A. ROBERTSON, Ecology Division, DSIR, Private Bag, Lower Hutt Classa ied Summarised Notes - gorth Island: L. HOWELL, 38 Olcahu Rd.. Kaitaia South Island: P. D. GAZE, Ecology Division, DSIR, Private Bag, Nelson S.W. Pacific Island Records: J. L. MOORE, 32 Brook St., Lower Hutt Editor of OSNZ news: P. SAGAR, 38A Yardley St., Christchurch 4 SUBSCRIPTIONS AND MEMBERSHIP Annual Subscri tion: Ordinary member $20; Husband & Wife mem- bers $30; funior member (under 20) $15; Life Member $400; Family member (one Notornis er household) bein other family of a member in the same houseg old as a member 510; Institution $40; Overseas member and overseas institution $5.00 extra (postage). Subscriptions are for the calendar year of first joining and are renewed b invoice each anuary. Please pay promptly to ensure receiving hYotornis and 0I NZ News. Applications for membership, changes of address and resignations should be sent to the Treasurer. Exchanges and library subscriptions should be sent to the Treasurer. Editorial matters ONLY should be sent to the Editor. [Registered with the GPO Gisborne as a publication] ISSN 0029-4470 CONTENTS JOUVWTIN, P.; MOUGIN, J. -L.; STAI-IL,J. -C.; WEIMERSKIRCH, H. Comparative Biology of the Burrowing Petrels of the Crozet Islands... CUNNINGHAM, D. M.; MOORS, P. J. The Birds of the Noises Islands, Hauraki Gulf... .. .. .. .. .. .... .... .. FENN]F:LL, J. F. M.; SAGAR, P. M.; FENNELL, J. S. Variation within the Redpolls of Canterbury . .. .. Short Notes CHILD, P. A Cattle Egret . .. .. .. .. MORRISON, K.; MORRISON, J. V. Unusual riverbed birds in the Eglington Valley, Fiordland . .. .. .. FENNELL, J.; SAGAR, P. Variation between Redpolls in Four Southern New Zealand Localities . McCALLUM, J.; BROOK, F.; FRANCIS, M. Buller's Mollymawks on Rosemary Rock, Three Kings Islands, in 1985... NOTMAN, P. Blue Penguin attacked by Fur Seal.. GILL, B. J.; TURBOTT, E. G. Barn Owls transported by aircrafi - a post script . .. .. .. Printed by TE RAU PRESS LTD.,Peel Street. Cisborne REGIONAL REPRESENTATIVES FAR N0RTH:L. Howell, 38 Okahu Rd., Kaitaia. Ph. 7424. NORTHLAND: D. E. Crockett , 21 McMillan Ave., Kamo, Whangarei. Ph. 50954. AUCKLAND: M. J. Taylor, 28 Awarua Crescent, Orakei, Auckland 5. Ph. 549234. SOUTH AUCKLAND: Beth Brown, 20 Redrnount Place, Red Hill, Papakura. Ph. 2988157. WAIKATO: F. ~ieuwland,38 Berkley Ave., Hamilton. Ph. 62045. BAY OF PLENTY: P. C. M. Latham, c/o Papamoa Beach P.O., via Te Puke Ph. 420406. VOLCANIC PLATEAU: J. G. Innes, Loop Road, Okareka. Rotorua. Ph. 28107. GISBORNE/ WAIROA: J. C. Henley, 9 Mason St. ,Gisborne. Ph. 81581. TARANAKI: D. G. Medway, 25A Norman Street, New Plymouth. MANAWATU: L. J. ~aies,71 Jickell Street, ~almektonNorth. WANGANUI: Ph. 70159. HAWKES BAY: K. V. Todd, 2/416 E. Heretaunga Street, Hastings. Ph. 82172. WAIRARAPA: C. 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Reports and bulletins (1939-1942) $2.00 OSNZ Library catalogue (1976 ed) 17 pp. $0.55 Bandin re orts, Nos8-14, 55ceach. Kermatec Ldition. 1964, by A. T. Edgar. $0.50 Amendments & Additions to 1970 Checklist $2.00 NOTORNIS is the journal of the Ornithological Society of New Zealand (Inc.) Editor: B. D. Heather, 10 Jocelyn Crescent SILVERSTREAM Volume 32 Part 3 September. 1985 COMPARATIVE BIOLOGY OF THE BURROWING PETRELS OF THE CROZET ISLANDS By P. JOUVENTIN, J. -L. MOUGIN, J. -C. STAHL and H. WEIMERSKIRCH ABSTRACT This paper presents, as well as some earlier data, the results of a study of the burrowing petrels of the Crozet Islands (South Indian Ocean) made during the East Island expedition of September 1981 to February 1982. The 16 petrels are discussed and analysed in the following taxonomic groups: 4 gadfly petrels, 5 pions, 2 Pro~elZariapetrels, 3 storm petrels and 2 diving petrels. For each group, biometric data and the breeding biology of each species are given. The timing of events (first return to land, laying, hatching, fledging), nest reoccupation, incubation schedule, chick growth and chick-feeding pattern were the main study topics. Abundance cycles during pairing, temporary egg desertions, nest selection, comparison with other localities and particularly ecological segregation of the petrels are discussed. INTRODUCTION The Crozet Islands, discovered in 1772 by the French navigator Nicolas Marion-Dufresne, lie in the Indian Ocean between longitudes 50'00' and 52O30 ' E and latitudes 45O50 'and 46O30' S. A recent study (Gamberoni er al. 1982) showed that the Antarctic Convergence is displaced northwards in the Crozet - Kerguelen region by the shelves of these island groups. The Crozet Islands are more than 300 km south of the Polar Front but north of the limit of the subsurface temperature minimum between 48O and 49O S. Thus, the chief hydrological characteristic of this region is the limited extent of subantarctic waters because the Antarctic and Subtropical Convergences are very close together (43' and 41' respectively). CROZET ISLANDS Ip km .e Apostle Islands 46OOO.S L Hog Island co 2 Q I I Z z-I INDIAN OCEAN o,z C Possession lsland I East lsland Q Penguin lsland -46 "30' S z S 1 50°30'E 151°00'E 151°30'~ I SZ0O0'E 0 3 3 J -Z V) FIGURE 1 - Location and map of the Crozet Islands 1985 BURROWING PETRELS OF CROZET ISLANDS 159 The Crozet Islands are scattered over about 150 km east to west and have an estimated total land area of about 500 km2. There are two groups of islands (Fig. 1); to the west, Hog Island, Penguin Island and Apostle Islands, and to the east, Possession Island and East Island. The islands are volcanic in origin and are small (the largest, Possession Island, is 18 km on its longest side), but the topography is complex and rises to quite a high altitude. The highest point is 1050 m on East Island. The coastline alternates between cliffs and beaches of sand or boulders. The interior consists of large glacial valleys separated by rocky ridges or high plateaus. The tundra-type vegetation (no trees occur on the Crozets) does not extend higher than 300 m ad. The climate is severe, even for the "roaring forties". The temperatures are cold, the mean annual temperature being + 4.6OC. There is a small variation in temperature between the warmest month (February, + 7.7OC) and the coldest (September, + 2.8OC), but the climate is characterised by violent winds, which have a mean annual speed of 12 m/s (43 km/h) and a maximum of 70 m/s (252 km/h). For example, in 1980 the wind blew at speeds of more than 115 km/h on 93 days. Sunshine hours are low overall (a monthly mean of 103 hours) and rainfall is high (2470 mm per annum). During winter, snowfalls are frequent but there is no permanent snow on the islands. We have shown elsewhere (Jouventin et al. 1984) that the Crozet Islands shelter a rich seabird community. East Island has the most birds of the group. Of the 34 seabird species breeding on the Crozets, 32 are on East Island, which lacks introduced predators (cats and rats). This island is the breeding ground of 23 procellariiformes (5 albatrosses, 13 procellarids, 3 storm petrels and 2 diving petrels) compared with 15 on Possession Island, 8 on Hog Island, 18 on Penguin Island and 15 on Apostle Islands. Of these 23 species, 15 nest in burrows. The only burrowing species of the Crozets missing on East Island is the White-headed Petrel (Pterodroma lessonii), which nests only on Possession Island. Studies of burrowing petrels of the Crozet group are therefore best done on East Island. A study of this kind was lacking. The whole breeding cycle of some of these petrels -Pterodroma brevirosrris (Mougin 1969), I?lessonii (Barre 1976), Procellaria aequinoctialis (Mougin 1970, 1971), and Procellaria cinerea (Barrat 1974, Despin 1976) - had been studied on Possession Island.