TANE 26, 1980 UNIVERSITY FIELD CLUB SCIENTIFIC TRIP TO THE MOKOHINAU ISLANDS, MAY 1979 Introduction and Acknowledgements

by A.E. Wright A.U.F.C. Vice-President 1975 - 1980

The Mokohinau Islands were chosen as the venue for Field Club's 1979 offshore island scientific trip primarily to allow a detailed study of one particular island, Fanal Island, which had received very little attention previously. A party of eleven left Auckland in the launch Westpoint early in the evening of 19 May, 1979 and arrived at the Mokohinau Islands approximately 3am next morning. At daybreak, seven people (Peter Bellingham, Elizabeth Brown, Greg Browne, David Greig, Peter Matthews, Wynne Spring-Rice and Anthony Wright) were put ashore on Fanal Island. The remainder of the party (Roger Harker, Gary Housley, John McCallum and David Riddell) were landed on Burgess Island soon after. On Fanal Island studies were carried out in the fields of archaeology, botany (bryophytes, lichens and vascular plants), entomology, geology, geomorphology and ornithology and the results in most of these fields follow. On and around Burgess Island and the adjacent Knights Group, studies were completed in the fields of benthic ecology, herpetology and ornithology. Both parties left the islands and returned to Auckland on 26 May, 1979. The Mokohinau Islands (latitude 35° 50'S, longitude 175° 10'E), the most isolated of the Island Groups, lie 100 km north- north-east of . The Group consists of Burgess Island, the adjacent Knights Group of smaller islands and rock stacks, and Fanal Island, lying some 5km to the south-east (Fig. 1). Previous workers have concentrated on Burgess Island and the adjacent islets, with Fanal Island receiving little more than passing comments. Burgess Island is the site of a permanently manned light house and is under the control of the Ministry of Transport. The remaining islands, comprising 108 hectares of flora and fauna reserve, have been included in the Hauraki Gulf Maritime Park.

BURGESS ISLAND

Burgess Island (52 hec.) is dominated by Lighthouse Hill (112m), a volcanic plug standing above the bulk of the island, on which the lighthouse is situated. Landings were made at the jetty in Landing Bay and accommodation kindly provided in an unused lighthouse staff

1 MOKOHINAU ISLAND GROUP

BURGESS ISLAND POKOHINU

MOTUPAPA ISLAND

FANAL ISLAND MOTUKINO

M \\ ZL4LAN

Fig. 1. Map of Mokohinau Islands showing place names used in the present study. Informal names axe shown in inverted commas. Note that Fanal Island actually lies some 5 kilometres south-east of the other islands. Insets show relation to other islands and position off the coast. 2 residence. The coastline is deeply indented by bays and narrow, steep-walled gulches, and there are many outlying reefs and stacks as well as four small vegetated islets just off the coast. Apart from the boulder beach in Landing Bay, the island is cliffed on all sides. The summit area, in general terms, is gently sloping to undulating. Several plates in Fleming (1950) clearly depict the geography of the island.

KNIGHTS GROUP

These small islands and rock stacks lying to the south-west of Burgess Island comprise 35 hectares of flora and fauna reserve. Many are un-named and we have followed the Wildlife Service's system of referring to these by tag letters (Fig. 1). The two largest islands, Atihau (Trig) Island and Hokoromea (Maori Bay) Island, support N.Z. flax (Phormium tenax) and pohutukawa (Metrosideros excelsa) with low petrel scrub and salt-tolerant communities on the remainder.

FANAL ISLAND

Fanal Island (73 hectares) lies 5 kilometres to the south-east of the remainder of the Kokohinau Group. The island is almost entirely cliffbound, making landing in all but the calmest of seas very difficult. In the past, the accepted landing point has been a small rock shelf at the base of the cliffs some 70 metres east of the south-western extremity of the island. Due to heavy seas, we were unable to land at this point, although a subsequent visit from on land located a sign proclaiming the island a Wildlife Sanctuary lying between rocks, its waratah poles having rusted away. Instead, we landed on the southern coast a few hundred metres from the eastern end of the island. This locality consisted of a more gently sloping set of stepped rocks on the eastern side of a small embayment, negotiable at most stages of the tide. Above the landing, we climbed through a short, steep stretch of pohutukawa scrub, followed by 20-30m of N.Z. flax grove, emerging beneath coastal forest canopy. We camped beneath the mature coastal forest on the gently sloping summit plateau, more or less above the landing point. Despite high winds from the north and south during our stay, this proved to be a more sheltered site than any of the larger valleys further westwards. The only disadvantages of our site were the distance from fresh water (which did not affect us as we had brought our own supply ashore) and the non-central position. By comparison, the previously used campsite located in the large central valley was more difficult to access and further from the western landing point. The stream in this valley had been used as a water supply previously, although its permanency was unknown. In 3 the vicinity of the campsite were 3 or 4 small pools of standing water which could be used, and there this stream reached the clifftop a slight but continuous trickle of water was found. A similar trickle was found in the southern valley, once again right at the clifftop. It seems unlikely that any water would be present during the summer months. The well-developed track leading from the western landing to the campsite in the central valley mentioned in earlier reports appears to have grown over as it could not be located during the present survey. Although the island is steeply cliffed on all sides, the summit is a gently sloping plateau, with the highest points along the northern coast rising to the summit at David's Lookout (Fig 1). Three main valleys drain the western bulk of the island with a less pronounced gully draining the eastern peninsula. A wide variety of stages of vegetation regeneration were encountered, from dense, almost impenetrable scrub to mature coastal forest. The variety of vegetation types indicates a history of modification of the island by fire.

HISTORY

Fanal Island shows considerable evidence of Maori occupation, and muttonbirders probably continued to exploit the seabird populations regularly up until about twenty years ago. Newcombe (1952) reported that "muttonbirders have a good track formed leading to their main camp in the bushed bottom of the southern of the two main valleys. Burgess Island and the Knights Group show no evidence of permanent Maori occupation although visits by muttonbirders were still occurring in 1964 (Bell 1964). The Mokohinau lighthouse on Burgess Island began operating in 1883 and the island has been occupied continuously since then. Esler (1978) records that goats were released at an early date, and sheep and cattle have been grazed, with dairy cattle still present. During the Second World War, a Royal New Zealand Air Force Unit was stationed on Burgess Island. Gillham (1960) records that Burgess Island was fired at intervals of about three years from the early 1920s in an effort to keep tussocky sedges in check. The vegetation of the islands in the Knights Group also indicates frequent burning in the past. Kiore (Rattus exulans) were found in large numbers on Burgess and Fanal Islands, and on most of the islands of the Knights Group.

PREVIOUS WORK The earliest known accounts of aspects of the natural history are those of an early lighthouse keeper, F.S. Sandager (1888, 1890). Miss Frances Shakespear, daughter of the caretaker of Little Barrier Island, 4 visited Fanal Island in 1902 and collected a small number of plant specimens which are now lodged with the Herbarium of the Auckland Institute and Museum. A number of visits to the islands by Officers of the Wildlife Service of the Department of Internal Affairs have resulted in unpublished file reports on the flora and fauna of the islands (Adams 1969, Bell 1964, Newcombe 1952). Two papers on botanical features have been published; the first (Gillham 1960) on Burgess Island and the second (Esler 1978) covering the whole Mokohinau Group. Fleming (1950) provides the only report on the geology of the group. Ornithology has received the most attention with accounts by Buddie (1947), Emmens (1954), Fleming (1946), Roberts (1953) and Sandager (1890). In addition, a number of papers and articles mentioning the Mokohinau Islands in passing or referring to organisms found there have been found and these are included in the Bibliography which follows.

ACKNOWLEDGEMENTS

All members of the party would like to thank: the Hauraki Gulf Maritime Park Board for permission to visit the islands; Mr Arthur Calvert of Auckland for transport to and from the islands; Field Club's Food Officer, Bill Nichol, for excellent catering; Mesdames Bellingham, Brown, Housley, Riddell and Wright for much-appreciated home cooking eaten on the long boat trips; and the Auckland University Underwater Club for the loan of their Starcraft and outboard motor. Members of the Burgess Island party would like to thank Principal Lighthouse Keeper Ray Walters for providing accommodation on the island and for assistance during arrival and departure; Dr Bill Ballantine for providing maps and aerial photographs; and Fred Brooke, Ross Crowhurst and Anne and Roger Grace who kindly loaned diving tanks.

BIBLIOGRAPHY

Adams, G.P. 1969: Saddleback - Post liberation check, Fanal Island. Unpublished Report, Internal Affairs Department, Wellington. File 35/2/5. Anon. 1970: Mokohinau Islands included in Hauraki Gulf Maritime Park. Forest and Bird 175:18. Ayling, A.M. 1974: Offshore kept forests. New Zealand Nature Heritage 2(22): 605-609. Bell, B.D. 1964: Inspection of Mokohinau Islands. Pelagian Fishing Co. Unpublished Report, Internal Affairs Department, Wellington. File 46/29/204. Boulenger, G.A. 1906: Description of a new lizard from New Zealand. Annals & Magazine of Natural History, Ser. 7,17:369 - 370. Buddie, G.A. 1947: Notes on the birds of Mokohinau. New Zealand Bird Notes 2(4): 69-70. Buddie, G.A. 1947: Breeding of the red-billed gull. New Zealand Bird Notes 2(4): 71-72. Buller, W.L. 1893: Notes on New Zealand birds. Transactions of the New Zealand Institute 25:53-63. Buller, W.L. 1893: Further notes on the birds of New Zealand. Transactions of the New Zealand Institute 25: 63-88. Connor, H.E. 1971: Cortaderia splendens Connor sp. nov. (Gramineae). New Zealand Journal of Botany 9:519-525. Doak, W. 1974: Serranids (2). New Zealand Nature Heritage 3(42): 1160-1164. Emmens, C. 1954: Birds on Moko Hinau Island. Notornis 5:253 Esler, A.E. 1978: Botanical features of the Mokohinau Islands. Tane 24:187-197. 5 Fawcett, J.D. 1971: Note on the occurrence of the black shore skink, Leiolopisma suteri, Port Jackson, , New Zealand. AW Zealand Journal of Science 14: 1112-1114. Fleming, C.A. 1946: Breeding of the red-billed gull. A preliminary census of the Mokohinau colony. New Zealand Bird Notes 2:27-29. Fleming, C.A. 1950: The geology of the Mokohinau Islands, North Auckland. Part I. General geology. Transactions of the Royal Society of New Zealand 78:255-268. Fleming, C.A. & Wodzicki, K.A. 1952: A census of the gannet (Sula serrator) in New Zealand. Notornis 5:39-77. Gillham, M.E. 1960: Plant Communities of the Mokohinau Islands, northern New Zealand. Transactions of the Royal Society of New Zealand 88:79-98. Gurr, L. & Kinsky, F.C. 1965: The distribution of breeding colonies and status of the red- billed gull in New Zealand and its outlying islands. Notornis 12(4): 223-240. Hounsell, W.K. 1935: Hydrographic observations in Auckland Harbour. Transactions of the Royal Society of New Zealand 64(3): 257-271. Hurley, D.E. 1957: Studies on the New Zealand amphipodan fauna. No. 14. The genera Hyale and Allorchestes (Family Talitridae). Transactions of the Royal Society of New Zealand 84 (4): 903-933. Newcombe, P.L. 1952: Mokohinau Group. Unpublished Report, Internal Affairs Department, Wellington. File 46/29/204. Ordish, R.G. 1966: A systematic revision of the New Zealand water beetles (Coleoptera : Hytisaidae). Records of the Dominion Museum Wellington 5(22): 217-264. Parris, B.S. 1971: Miscellaneous plant records from northern offshore islands. Tane 17: 169-171. Ponder, W.F. 1966: The New Zealand species previously known as Zelaxitas Findlay, 1927 (Mollusca Gastropoda). Records of the Dominion Museum Wellington 5(17): 163-176. Roberts, R.V. 1953: Some birds of the Mokohinau Group. Notornis 5(6): 197-198. Rudge, M.R. 1974: Goats. New Zealand Nature Heritage 3(41): 1137-1146. Sandager, F.S. 1888: List of fishes sound round the Mokohinau sic Islands; their spawning time; and observations regarding some of the species. Transactions of the New Zealand Institute 20:127-133. Sandager, F.S. 1890: Observations on the Mokohinau Islands and the birds which visit them. Transactions of the New Zealand Institute 22:286-294. Sharp, D. 1881: On aquatic carnivorous Coleoptera or Dytiscidae. Scientific Transactions of the Royal Society of Dublin 2(2): 179 -1003. Silen, L. 1946: On two new groups of bryozoa living in shells of molluscs. Arkiv fur Zoologie 38(1): 1-7. Thompson, R.M.C. 1977: A bibliography of Offshore Islands of New Zealand. Miscellan• eous Publications of the New Zealand Oceonographic Institute 80. 210p. Veitch, C. 1969: M.V. Colville's trip to Little Barrier, Mokohinaus and Cuvier Islands. Auckland Botanical Society Newsletter26(3): 1-5. Veitch, C.R. (Compiler) 1973: Island survey form - Mokohinau - 25/11/73. Unpublished Report, Wildlife Service, Department of Internal Affairs, Wellington. Veitch, C. 1974: Island surveys. Wildlife-A review 5:38-40. Wodzicki, K.A. & Robertson, C.J.R. 1974: The gannet. New Zealand Nature Heritage 2(22): 593-597.

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