Kiwi Recovery Plan

Dr David Butler, Threatened Species Unit, Department of Conservation, Wellington.

Dr. John McLennan, DSIR Land Resources, Private Bag, Havelock North.

Threatened Species Recovery Plan Series No. 2

Department of Conservation P.O. Box 10-420 Wellington NEW ZEALAND

ISSN 1170-3806 ISBN 0-478-01303-5 Table of Contents

1.0 Introduction 1 1.1 Aims and Purpose of the Recovery Plan 1 1.2 Acknowledgements 1 1.3 Introduction to Kiwis 2 2.0 Taxonomy 2 3.0 Past Distribution and Abundance 2 3.1 North Island 2 3.2 South Island 3 3.3 Stewart Island 4 3.4 Offshore Islands 4 4.0 Present Distribution and Status 4 4.1 Little Spotted Kiwi 4 4.2 Great Spotted Kiwi 5 4.3 Brown Kiwi 5 Distribution Map 7 5.0 Threats to Kiwis and Current Population Trends 8 5.1 Little Spotted Kiwi 8 5.2 North Island Brown Kiwi 8 5.3 South Island Brown Kiwi 9 5.4 Stewart Island Brown Kiwi 10 5.5 Great spotted Kiwi 10 6.0 Relevant Aspects of the Ecology of Kiwis 11 6.1 Vulnerability to Predation 11 6.2 Habitat Requirements and Diet 12 6.3 Social Behaviour and Dispersion 13 6.4 Breeding Behaviour and Success 13 7.0 Ability to Recover 15 8.0 Options for Recovery 15 8.1 Do Nothing 15 8.2 Management in Situ 15 8.3 Translocations 15 8.4 Captive Breeding 16 9.0 RECOVERY STRATEGY: Goal, Aims and Objectives 17 9.1 Long-term Goal 17 9.2 Aims 17 9.3 Objectives 17 10.0 WORK PLAN 18 11.0 CRITICAL PATH 31 12.0 BUDGET 34 13.0 REFERENCES 34 1.0

Introduction to the Recovery Plan

AIMS AND PURPOSE see what needs doing and how they can best This recovery plan presents a five-year fit into the programme. Training further programme of management and research people and involving voluntary groups will aimed at a long-term goal of maintaining be important in implementing this plan. and, where possible, enhancing the current ACKNOWLEDGEMENTS abundance, distribution and genetic diversity This plan was prepared in consultation of kiwis. It has been approved for a five- with the proposed Kiwi Recovery Group, year period from July 1991 and will be due comprising experts on kiwis together with for review at the end of that period, or Protected Species staff from the Department sooner if new information leads to a of Conservation's following conservancies: proposal for a significant change in Southland, West Coast, Canterbury, Nelson/ direction. It will remain operative until a Marlborough, Wellington, Wanganui, Bay reviewed plan is in place. of Plenty, Hawkes Bay, East Coast, The plan is approved by the Director- Tongariro/Taupo, Waikato, Auckland and General of Conservation as a guide to the Northland. Department in its management of kiwis. Its The following attended meetings with the mplementation will be overseen by a Kiwi i authors to formulate plan drafts: Recovery Group and will be dependent on John Cockrem (Massey University), and vary with the resources and information Rogan Colbourne (DOC, Science & available at any point. The Research), Ron Goudswaard (Wellington recommendations contained in this plan do Zoo), Jim Jolly (private consultant), Murray not necessarily represent the views of all Potter (Massey University), John Lyall, those involved in its production, who are Raewyn Empson, Wayne Hutchinson, Mike acknowledged below. McGlynn, Cam Speedy, Phil Thomson, All kiwi species are included in the one Shaarina Boyd, Ray Pierce (DOC plan because they share many problems and conservancies). possible solutions. All are considered threatened with extinction unless the causes The plan also benefited from the of declines are addressed. For those in most comments of many individuals both within immediate danger, establishing populations and outside the Department of Conservation, on offshore islands and perhaps captivity particularly the New Zealand Conservation may continue to be necessary. But this plan Authority and its regional Conservation Boards, and the Royal Forest & Bird aims to retain kiwis on the mainland, recognising that in the long run the best way Protection Society. of preserving the diversity of New Zealand's INTRODUCTION TO THE KIWIS fauna and flora is to conserve the species as part of the community they have evolved in. Kiwis are the smallest members of the ratites, a group of flightless birds which There is only a small group of individuals includes the rheas of South America, the with the skills to undertake significant cassowaries of Australia and New Guinea, research and management of kiwis, and and the ostriches of Africa. They are including all species together allows them to 1 endemic to New Zealand and ancient in take an exceedingly long time to hatch. origin; their ancestor, which may also have Males are the smaller of the two sexes and spawned the moas, probably arrived in New perform most of the parental care. This Zealand some 70 million years ago reversal in sex roles is associated with (Fleming, 1962). monogamy, a combination which is extremely rare among birds. Kiwis are biological oddities, unique in both appearance and behaviour. Many of The genus Apteryx is truly a "one-off their features are more typical of mammals design, and it is not surprising, then, that than birds, a characteristic which prompted kiwis have become an important part of our Calder (1978) to describe them as New culture, an unofficial national emblem Zealand's honorary mammals. Kiwis hold a proclaiming our uniqueness. They are, variety of records among birds; their eggs without question, among the most distinctive are extremely large and rich in energy, and and interesting elements of our fauna.

2.0 Taxonomy

The names used throughout this recovery Island, australis in the South Island, and plan are those listed by Turbott (1990) in the lawryi on Stewart Island). The taxonomy of Checklist of the Birds of New Zealand. kiwis is currently under review, and some Three species of kiwi are recognised (the changes to the status of brown kiwi are little spotted kiwi, A. owenii, the great likely (C. Daugherty pers. comm.). The spotted kiwi, A. haastii, and the brown kiwi, implications of these changes are considered A. australis) with the last being divided into in later sections. three sub-species (mantelli in the North

3.0 Past Distribution and Abundance

NORTH ISLAND some of the specimens in his collection were Sub-fossil bones and archaeological caught there. remains show that all three species of kiwi Brown kiwis and little spotted kiwis were were once more widespread than they are spread throughout the North Island in the now. Great spotted kiwis seem never to have late Holocene (Reid & Williams, 1975; reached the North Island, despite the land- Millener, 1981), but little spotted kiwis were bridges that existed in the Pleistocene, and all but extinct there by the time the first Rothschild's (1893) repeated assertions that Europeans arrived. Two little spotted kiwis 2 were collected in the North Island in the there in the past making similar calls was a 1880's, one of which was found in the brown kiwi (R. Colbourne, pers. comm.). It alpine zone of the Tararua Range (Buller, was formerly common throughout most of 1888; Reischeck, 1930). the South Island, and was thought to be still It is not clear when brown kiwi began to plentiful on the West Coast as recently as decline in the lower half of the North Island. 1975 (Reid & Williams, 1975). Their remains have been found in middens The sub-fossil remains of brown and at Paremata (just north of Wellington), and great spotted kiwis are difficult to their bones are common in caves in the distinguish, so their former distributions are Wairarapa (Millener, 1981). The birds not well known. (A promising technique for apparently died out in the Tararua Ranges separating the tibia bones of these species is before Europeans arrived. Their retreat now being developed by T. Worthy, but it is northwards seems to be continuing, and only still provisional and has not yet been applied a handful of birds now survive in the widely). According to Reid and Williams northern tip of the Ruahine Range (1975), sub-fossil and midden remains (McLennan, in prep.). There is however an indicate that brown kiwi were formerly isolated record in the centre of the range (R. widespread in Marlborough and the coastal Colbourne, pers. comm.). regions of Kaikoura, Canterbury and Anecdotal evidence suggests that kiwis northern Otago. Oliver (1955) reported that were generally far more numerous in the brown kiwis were seen in the Marlborough forests of the North Island than they are Sounds in 1931, and were present in the now. Buller (1888), for example, reported forests bordering Otago Harbour in 1873. very high densities of kiwi on Mt Hikurangi, (Roderick (1983) notes that Doubtful Sound yet the birds are rare there today. Similarly, was also once known as Otago Harbour and it is now hard to find a kiwi in the suggests that Oliver's report relates to Kaimanawa Ranges, yet Buller (1877) refers there). T. Worthy (pers. comm.) has found to a collection of 300 skins that were taken brown kiwi bones in the Takaka Hills. The from there by professional hunters. Kiwi northernmost population of brown kiwi in densities which are exceptional by today's the South Island today is at Okarito on the standards, such as those in Waipoua in West Coast. Northland, seem to have been common in There is some evidence that great spotted the North Island at the turn of the century. kiwis have contracted in range in recent SOUTH ISLAND geological times. A sub-fossil from Pyramid Valley is thought to be of this species, and The South Island mainland contained all suggests that the birds were once more three kiwi species when European settlers widespread east of the Alps than they are arrived. Little spotted kiwis declined soon now (Reid and Williams, 1975). The present afterwards, and are now probably extinct. population of great spotted kiwi comprises The last confirmed specimens in the South three more-or-less discrete clumps, which Island were ones collected near Lake further indicates a recent contraction of Poteriteri in Fiordland in 1938 and bones range. Oliver (1955) reported that some from a dead bird from Junction Burn, specimens in the Canterbury museum were Fiordland in 1974 (Turbott, 1990). There is collected in Fiordland. These may have been a remote possibility the species may still mis-labelled, because there are no other survive in Westland; calls which resemble historical records of great spotted kiwi from those of the little spotted kiwi have been this area. heard recently in the Arawhata Valley (J. Jolly, pers. comm.), though a bird caught 3 STEWART ISLAND The population may be natural, but this Nothing is recorded of the origins and obviously requires that some birds survived both the prolonged occupation of the island historical distribution of kiwis on Stewart by Maori, and the more recent attempts to Island. Brown kiwis are the only species farm it. present there today. OFFSHORE ISLANDS The origins of the brown kiwi on Little Barrier Island are now uncertain. Two Both little spotted kiwis and brown kiwis specimens were collected there in 1862 and were present on at least one offshore island 1887, although the natural population was when Europeans first arrived. Little spotted thought to be extinct when other brown kiwi kiwi occur naturally on D'Urville Island, from elsewhere in the North Island were although the birds are all but extinct there liberated on the island between 1910 and today. Their population on Kapiti Island is 1940 (Oliver, 1955). This presumed widely believed to result from an extinction is now suspect, since the birds on introduction earlier this century (Oliver, the island have their own unique type of lice 1955) but there are no records of the birds which are clearly not of mainland origin being liberated there (J. Jolly, pers. comm.). (Ricardo Palma, in press).

4.0 Present Distribution and Status

The following account is based on The the same time (Jolly and Colbourne, in atlas of bird distribution in New Zealand press). (Bull et. al, 1985) and on recent unpublished Other Kapiti birds were moved to Red information held mainly by Rogan Mercury (off the Coromandel coast) in 1983 Colbourne of DOC, Wellington. A map and to Hen Island (in the Hauraki Gulf) in outlining the range of the different species 1988/89. The population on Red Mercury follows section 4.3. had increased from 12 to 17 by March 1989. LITTLE SPOTTED KIWI The present size of the Hen Island population is not known, but some of the 30 Little spotted kiwis are now probably birds that were originally released there confined to offshore islands. Their largest were still present in 1990 (Jolly and remaining population is that on Kapiti, Colbourne, in press.). where 500-1500 birds occupy some 1900 ha of mixed forest, scrub and grassland. The These new populations have reduced the D'Urville Island population has failed risk of extinction for this species, but the (probably because of predation by stoats) Kapiti population will remain for some time but two birds from there (a male and a as the only one of any consequence. The female) were successfully shifted to Long birds were considered by Williams and Island in the Marlborough Sounds in the Given (1981) and Bell (1986) to be 1980s. One has since paired with a Kapiti ` endangered', and that classification is still bird, which was released on Long island at appropriate today. 4 GREAT SPOTTED KIWI kiwi on Little Barrier in 1915, but this seems The present distribution of great spotted to have failed (Oliver, 1955). kiwi is not known in detail. The birds are The great spotted kiwi was not found only in the South Island, mainly west considered a threatened species by Bell of the Alps, between Whanganui Inlet (in (1986), but according to the Species the north) and the Karangarua River (in the Ranking System currently being developed south). Densities are highest (about four by the Department of Conservation it should pairs per km2) in the sub-alpine zone of the now be treated as one and requires work `in mountain ranges immediately adjacent to the short term'. the Tasman Sea (Jolly and Roderick, 1983; BROWN KIWI McLennan and McCann, unpublished). There are currently three more-or-less The North Island sub-species of brown discrete populations of great spotted kiwi, of kiwi is found only in the upper two-thirds of which the largest extends from Northwest the North Islandr.above about latitude 40°S, Nelson to the southern tip of the Paparoa but with a northern limit at about a line Ranges. The second population, some 50 between Mangonui Harbour and Kaitaia. km south-east of the Paparoa birds, is The birds are widespread in Northland, in a intermediate in size and the furthest inland. diverse range of vegetation types including It is centred on Arthur's Pass and extends exotic forests and rough farmland eastwards into the headwaters of the (Colbourne and Kleinpaste, 1983;). Waimakariri and Hurunui Rivers, and Densities in parts of Waipoua and northwards to Lake Sumner. The third and Tangiteroria forests exceed 20 pairs per most southern population is in Westland, in square kilometre (R. Pierce, pers. comm., the foothills of the Alps between the Potter, 1989). Densities in some exotic Waitaha and Karangarua Rivers. This sparse forests in Northland reach one pair per 5 ha, and small population might actually extend similar to that in nearby native vegetation as far south as the upper reaches of the (Colboume and Kleinpaste, 1983). Haast River, where a few kiwi of uncertain The Northland population extends south identity are present (J. Jolly, pers. comm.). to a line running westwards from A few great spotted kiwis might live outside Mangawhai Heads to the top of the Kaipara the known limits of these three populations. Harbour. Repeated attempts in recent years There are still occasional unconfirmed to re-introduce kiwis into the Waitakere records from the Howard and Tiraumea Ranges have been unsuccessful (MacMillan, Valleys, on the western perimeter of Nelson 1990). Lakes National Park. Kiwis were definitely in these valleys at the end of last century, Bull et al. (1985) show kiwis as being but searches by C.D. Roderick between present in the Hunua Range bordering the 1980 and 1983 and by J. Jolly in January Firth of Thames, 15 km south-east of 1990 have been unsuccessful. These birds, if Auckland City, but this single record is confirmed, would extend the known range probably doubtful. The birds are on the of the northern population of great spotted other side of the Firth of Thames, in the kiwis by some 20 km to the east. forests of the Coromandel Peninsula. This population is sparse but extends southwards There are apparently no populations of along the Kaimai Range (where they may great spotted kiwis on offshore islands, now be extinct) to the Mamaku Plateau. though a bird heard and seen on Secretary Island off Fiordland in 1970 may have been The brown kiwis in the central regions of this species (M. Foord, pers. comm.). An the North Island belong to one of two attempt was made to establish great spotted discrete populations, separated from each other by the Waikato Basin and the 5 Kaingaroa Plateau. The larger of these seems to be predominate there today (J. populations fans out westward from the Jolly and R. Colboune, pers. comm.). They shores of Lake Taupo to Kawhia Harbour in owe their origins to two birds from Dusky the north and Wanganui in the south. It Sound and five from Jacksons Bay. As includes those birds in the extensive hill mentioned above, North Island brown kiwi country of inland Taranaki and the King were released on Little Barrier Island at least Country, and the forests of Egmont National twice between 1910 and 1940. Park. Little is known of kiwi densities The largest population of brown kiwi in throughout this region. A localised and the South Island is in Fiordland, between the superficial survey at Aotuhia in Taranaki in Hollyford and Waitutu Rivers (Fig. 1). November 1985 indicated that the scrubland These birds extend east to the shores of there contained about one pair of kiwis per Lakes Manapouri, Monowai, Hauroko and 15 ha (McLennan, 1985). Poteriteri, and the Livingstone Range east of The second population in the central Lake Te Anau. The birds are present in North Island lies to the east of Rotorua, and moderate numbers on Resolution Island, extends from the Raukumara Ranges in the where they occurred naturally but were also north to the Ruahine Range in the south. the subject of liberations by Richard Henry The birds are often heard and caught in gin earlier this century. They are also present on traps in the north-eastern corner of Urewera Secretary and Parrot Islands. Call counts National Park, and in the foothills along the elsewhere in Fiordland indicate adult eastern edge of the Bay of Plenty. Numbers densities of 6 to 10 per km2 (Napper, 1989, diminish south of Lake Waikaremoana, and quoting R. Colbourne). finally peter out altogether in southern Two smaller populations of brown kiwi Hawke's Bay. Average densities in the lie to the north of Fiordland - at Haast, Kaweka Ranges, near the southern limit of between the Haast and Cascade Rivers, and their distribution, are less than one per 100 at Okarito, between the Waiho and Okarito ha (Speedy, 1985). Few kiwis live in coastal Rivers some 150 km further up the coast. and lowland areas of the east coast, nor in its Little is known of the Haast population, extensive exotic forests (McLennan, except that it is believed to be small (J. Jolly, unpublished). pers. comm.). The Okarito population is The southern limit of brown kiwis on the confined to a few thousand hectares and eastern side of the North Island is probably currently estimated at 30-50 birds the northern tip of the Ruahine Range, (Colbourne and Lyall, 1990). where a handful of birds live in catchments Brown kiwi are spread throughout draining to both the east and the west Stewart Island and two small islets (Ulva (McLennan, unpublished). A few kiwis live and Horomamae) off its eastern coast. slightly further south at Gwavas in southern Densities of adults around Masons Bay Hawke's Bay, but these were brought down average some 25-30 birds per km2, but these from Northland in the 1980s. decline to about 12 per km2 at Scollays Flat, The natural range of North Island brown some 20 km further south (Napper, 1989, kiwi has been extended in European times quoting R. Colbourne), and even lower in by liberating birds on offshore islands. the higher country in the north (e.g. Mt Small numbers are present on Kawau and Angelm) (A. Cox, pers. comm.). Ponui Islands in the Hauraki Gulf, and on Both the North Island and South Island Moturoa Island in the Bay of Islands. Brown brown kiwis are considered `threatened' by kiwis from both the North and South Islands Bell (1986), and this is still the case were released on Kapiti Island in the early according to the results of the new Species 1900's, but the South Island form (australis) Ranking System. 6

5.0

Threats to Kiwis and Current Population Trends

LITTLE SPOTTED KIWI Both Jolly and Colbourne do agree that The factors that caused the extinction of there is a low turnover of adults on Kapiti, little spotted kiwi on the North Island are that the present population comprises about unknown. Their demise there largely 250-750 breeding pairs, and that the birds preceded European settlement. Midden live at high densities (one pair per 1.6 ha, remains show that the birds were hunted by n=12) relative to other species of kiwi on the mainland. Whatever the present trend, the Maori and their dogs, but so too were brown population on Kapiti is unlikely to fail in the kiwis and they continued to flourish in most next decade, provided other factors remain areas. unchanged. The recent decline of little spotted kiwi to NORTH ISLAND BROWN KIWI near extinction in the South Island passed almost unnoticed. Stoats possibly caused The persistence of both brown and great their demise (Hill and Hill, 1987; Reid, spotted kiwis on the mainland is interesting. 1978), a view supported by the observation Ancient endemics are generally very that the birds live today only on islands sensitive to habitat changes and competition, where these mammals are absent. while kiwis in particular seem likely to be The current status of little spotted kiwi on extremely vulnerable to mammalian Kapiti Island is not clear, with two predators. Their resilience must be due in independent studies giving contradictory part to both their large size, which exceeds that of the prey commonly eaten by cats and results. Jolly (1985 & 1989) believed that the birds may not be producing enough mustelids in New Zealand forests (though a stoat has been observed with a dead kiwi chicks to replace themselves, because wekas and to eat most of their eggs. Jolly estimated that chick, (R. Colbourne, pers. comm.) the 250-750 breeding pairs of kiwis on the their ability to live in a wide range of habitats. island produce about 40 chicks each year, of which it could be predicted that only 20 Brown kiwis have, nevertheless, lost survive to maturity. On this basis, each pair ground since the arrival of humans, and would take on average 50 years to replace continue to do so in some areas. Land themselves, and it is highly unlikely that clearance by both Maori and Europeans has adults live long enough to do this. eliminated the birds in most coastal and lowland areas of the North Island. The R. Colbourne, on the other hand, claims that juveniles make up some 35% of the forests that remain in such areas have not present population - and are about six times provided adequate refuges for the birds more common than Jolly's figures predict. because (among other things) they are generally too small to support viable Colbourne's ratio is based on some 106 1987). In kiwis, which were found by his trained dog populations (McLennan et. al, Hawke's Bay, for example, remnants as from 1986 to 1989 inclusive. This large as 500 ha usually lose their kiwis information suggests that the population is in good heart, and is probably producing far within two decades of becoming isolated (McLennan, in prep.), though whether this more chicks each year than the island can applies generally to other areas is not yet support. known.

8 The full effects of land clearance have evidence of shrinkage northward of the still to be felt in some areas. In both southern limit of the range (R. Pierce, & P. Taranaki and Northland, land clearance has Anderson, pers. comm.). Kiwis have been so recent that many small remnants of colonised some exotic forests in this region vegetation still contain the birds. These (Reid and Williams, 1975), implying that kiwis may not be indicators of vigorous and those in nearby native forests are producing expanding populations, as some surplus young. Waipoua State Forest on the optimistically believe. They may instead be west coast currently contains 3000 to 5000 the indirect and less obvious casualties of kiwis - probably the largest population now land clearance, trapped in a no-win situation. extant in the North Island. Some populations They and the others like them may gradually in Northland have, however, declined in disappear and not be replaced. We don't recent times. In a six week period in late know how many birds in Northland and 1987, a feral dog killed about 50% of the Taranaki are currently in this predicament, 1000 kiwis living in Waitangi State Forest in but it could be as many as 20%. Whatever the Bay of Islands (Taborsky, 1988). The the figure, they will probably decline in predation was noticed and stopped (by these regions over the next two decades, shooting the dog) only because the birds even if nothing else changes. were being studied at the time; clearly on most occasions the birds would not have a Of greater immediate concern are the willing benefactor on hand to protect them. brown kiwi in the large tracts of forest and The losses at Waitangi are not significant in scrub that remain in the North Island. Little a national context, but they do illustrate both is known of their status, since few of their the vulnerability of kiwis to predators and populations have been surveyed. The little the speed at which seemingly healthy available information suggests that the birds populations can fail. They also serve to warn are declining, at least in the southern half of us that we should not be complacent about their range. the future of brown kiwi in Northland, In Hawke's Bay, for example, two simply because there happens to be plenty populations (at Haliburtons and Waitere) there now. Northland lost c7% of its forest have declined by about 50% in the last four habitat in five years in the late 1970s-early years (McLennan, unpublished). Anecdotal 1980s through government incentives for evidence suggests that declines of similar land clearance, a situation that could re- magnitude are occurring throughout the occur. In addition we should recognise that region, including the extensive forests of possums have only recently spread here. Urewera National Park. Their cause(s) have They may have a direct impact on kiwis not been identified, but McLennan et al (e.g. burrow competition & egg predation), (1987) believe that gin-trapping and cyanide or an indirect one through increased poisoning for possums (which also kills trapping and poisoning operations to control kiwis) and predation by cats on juveniles are them. A final cause for some concern is that the main contributors. three of c 15 known birds in part of Waipoua A similar trend may be emerging from forest were killed on roads over an eight- the Bay of Plenty, in that kiwis seem to have month period. disappeared from some of the sites where SOUTH ISLAND BROWN KIWI Taylor and Calder (1983) recorded them in Unlike their northern counterparts, South However 1981 (Miller, unpublished). Island brown kiwis are not today under further work is needed to confirm this. immediate threat of land clearance. Most of The situation in Northland seems to be their populations are on land which is either much better, with the birds apparently formally protected, or currently considered flourishing in most areas, though there is too steep for forestry and farming. 9 The processes that led to the extinction of brown kiwis are not encountered "til the brown kiwis in the forests of Nelson, Hollyford is crossed" and this river still Golden Bay and the Marlborough Sounds marks the northern limit of the population are not known. It is noteworthy, however, today. Recent surveys suggest that kiwis that the birds had largely disappeared before have disappeared since the turn of the cats and mustelids were introduced, and that century from Martins Bay and the Pyke little spotted kiwis continued to flourish in Valley, but the birds are still present in the same areas for some decades afterwards. reasonable numbers around Doubtful and Such events should remind us that processes Dusky Sounds and the adjoining fiords (R. other than habitat destruction and predation Colbourne and J. Jolly, pers. comms. ). Little can cause extinction, and that populations on is known of their status elsewhere in offshore islands are probably not as safe as Fiordland, though they are considered we imagine them to be. common in the Kepler, Murchison and The population at Okarito was surveyed Stuart Mountains (D. Crouchiey, pers. by the Wildlife Service between June 1979 comm.). They have apparently been rare and 1983 (Roderick, 1983) and again by south of Preservation Net for the last 50 Colbourne and Lyall (1990) in July 1990 years (J.Jolly,pers. comm.). and February 1991. Roderick (1983) defined STEWART ISLAND BROWN KIWI the boundaries of the population precisely, Stewart Islanders often report that kiwis identifying 20 territories, and estimated its have become more numerous there in the size as being in the "low hundreds." last few decades. A report that the birds Colbourne and Lyall's survey increased the were thought to be so rare there at the turn reported range of the birds, and recorded 18 of the century that the Southland individuals indicating a total population of Acclimatization Society considered boosting only about 30-50. Both surveys indicate that the population with birds from Fiordland recruitment may not be sufficient to replace (Roderick, 1983) might support such an lost adults, e.g. Roderick (1983) reported idea. However other authors do not suggest that a banded male who lost his mate in a that the birds were at all rare either late last gin-trap was still unpaired 10 years later; century or early in this one (Buller (1888), and Colbourne and Lyall found that some of Guthrie-Smith (1914). the territories which were occupied in 1979 had become vacant. Colbourne and Lyall Surveys show that the birds are now (1990) concluded that the Okarito widespread and abundant on the island, population is declining, and suggested that especially round Masons Bay, where stoats, dogs, and gin-trapping were the main densities are similar to those in Northland contributory factors. However further (Napper, 1989, quoting R. Colbourne). assessment is needed to clarify the Recent studies show that the birds breed comparison between the two surveys. successfully in the presence of cats, and that chick survival is high (R. Colbourne, pers. The presence of brown kiwis near Haast comm.). The prospects for this population was first documented by the explorer appear favourable for the foreseeable future. Charles Douglas in the 1870s (Pascoe, 1957). The size, distribution and status of GREAT SPOTTED KIWI this population is not well known, but it is Great spotted kiwis appear to be clearly both small and sparse. Roderick maintaining their numbers in alpine and sub- (1983) thought that it might total 100 to 200 alpine regions of northwest Nelson. In the birds, but it is not clear how he arrived at Saxon area of the Heaphy track, pairs live in this figure. exclusive territories, which abut those of Charles Douglas wrote that Fiordland their neighbours. The territories extend over 1 0 all of the available habitat, apart from a few predators which are either rare or absent in gaps here and there which are too small to mountain environments. Lowland birds support a pair of kiwis. Few territories are which are living on the fringes of farmland occupied by single males or females; and settled areas are declining quickly. At territory owners which lose their partners Kahurangi Point, for example, 4 of eleven usually re-mate within 12-36 months, often kiwis have been caught at least once in gin- with another adult that has moved in from traps, to judge from their mis-shaped and/or elsewhere. The breeding success of the birds missing toes. One of the eleven study birds at Saxon is low, and juveniles are rare, but was killed recently by a pig dog, and another the population as a whole seems to be has disappeared. Losses in this locality producing more individuals than the habitat exceed recruitment, and some parts of the can support (McLennan and McCann, forest are now no longer occupied by kiwis unpublished). (McLennan and McCann, unpublished). Great spotted kiwis in lowland and Little is known of the status of the coastal forests are not faring as well as their populations further south, except that the counterparts in the mountains. The birds are one in the Smythe Range and headwaters of less numerous in lowland areas, and share the Wanganui River is both sparse and small their habitat with a number of mammalian (Roderick, 1983; J. Jolly pers. comm.).

6.0

Relevant Aspects of the Ecology of Kiwis

VULNERABILITY TO PREDATION Kiwis have also evolved for some 25 Kiwis have evolved with a variety of million years in the presence of wekas predators, most recently the mammals (Fleming, 1962), the only extant natural introduced by Maori and Europeans. But predator of kiwi eggs and newly-hatched before these there were large predatory chicks. All species appear to have developed birds, including an eagle (Harpagornis), defences against wekas, including such now known only from their sub-fossil elaborate ploys as placing vegetation over remains. the entrance of their breeding burrows to make them less conspicuous (McLennan The impact that these predators had on 1988, Jolly 1989). ground-dwelling birds will never be known, but much of the kiwi's behaviour today may The vulnerability of kiwis to mammalian be a legacy of their past association with predators is therefore not because the birds these hunters. All three species are lack anti-predator defences; it is instead cryptically coloured and hide during because the ones they have are ineffective. daylight, emerging to feed only under the They evolved to foil day-active birds which cover of darkness. The Stewart Island brown hunted by sight, not nocturnal mammals kiwi, with its occasional bouts of daytime hunting by sound and scent. Adult brown feeding, is the only exception. and great spotted kiwis may be sufficiently 1 1 large and aggressive to thwart attacks from kiwis inhabits upland areas, and a somewhat rats, cats and probably stoats, the three most smaller form lives in lowland and coastal abundant predators in New Zealand forests. forests (McLennan and McCann, Their young are, however, vulnerable to unpublished). This specialisation implies these predators, and both young and adults that a portion of the population is adapted to are vulnerable to dogs and pigs. Little upland areas, and that the birds there today spotted kiwis have been the main victim of are not merely a remnant of a once more the new predators; at half the size of the extensive population. other kiwis, they may be simply too small to Great spotted kiwis in Northwest Nelson defend themselves against stoats and cats. feed along the fringes of rough farmland, HABITAT REQUIREMENTS AND DIET but seldom live in it permanently. They also feed in stunted forest and scrub on sand- All kiwis occupied a variety of habitats, dunes, and along the margins of tidal spanning a wide range of altitude, estuaries which abut forest. Great spotted temperature, rainfall, terrain, soil and kiwis have not colonised pine forests, vegetation types (Reid and Williams, 1975). although there are some within their present Brown kiwis reach their highest densities geographical range. in lowland and coastal indigenous forest, Little is known of the habitat preferences which probably indicates that this is their of little spotted kiwi. The birds on Kapiti preferred habitat. Potter (1989) Island occupy all of the vegetation types demonstrated experimentally that brown there, including flax, mixed scrub, seral and kiwis in Northland prefer regenerating forest older forest, and rough grassland, though to rough farmland, and McLennan et al only where the last adjoins forest (R. (1987) found in Hawke's Bay that the birds Colbourne, J. Jolly pers. comms.). Densities prefer mature indigenous forest to mature may be lower in mixed scrub/grassland scrubland. However Potter (1990) also areas. showed that birds made considerable use of forest remnants that were separated from Little spotted kiwis formerly overlapped major tracts of forest by areas of farmland. in distribution with brown kiwis in both the North and South Islands. Richard Henry Kiwis colonise exotic pine forests in (quoted by Hill and Hill, 1987) observed in Northland and Taranaki, generally when the Fiordland that little spotted kiwis generally stands reach an age of about 10 years preferred lighter, drier forest, while brown (Colbourne and Kleinpaste, 1983). Despite kiwis preferred moist and shady areas, their structural simplicity and acidic litter, however the two did move over `the same these exotic forests seem to be quite suitable ground'. Any segregation between the two for kiwis, since the birds living within them species is not obvious on Kapiti Island achieve similar body weights, productivity today, the only place where they still live and densities to those in indigenous forests together. The 50 or so brown kiwis on (M. Taborsky, pers. comm). There are, Kapiti do live mainly in moist areas, but however, few kiwis in exotic forests in the they share them with little spotted kiwis (J. Bay of Plenty and Hawke's Bay, Jolly and R. Colbourne, pers. comm.). presumably because few young are being produced nearby to colonise them Nothing is known of the ecological (McLennan, unpublished). factors that led to the development of brown and great spotted kiwis as separate species. In contrast to brown kiwis, great spotted The ranges of the two species don't overlap kiwis reach their highest densities in wet, today, and may never have. Great spotted mossy, sub-alpine vegetation. Recent studies kiwis have a shorter, stouter and straighter suggest that a large form of great spotted bill than brown kiwis, but the diets of both 12 species are similar. Earthworms, cicada pairs or groups. This in turn implies that nymphs and beetle adults and larvae are they need large areas of forest or scrub (in their main foods, supplemented by a few the order of 5 000 - 15 000 ha) to maintain seeds and leaves and a wide variety of other self-supporting populations (McLennan et. invertebrates (Reid, et. al, 1982; Colbourne al, 1987). Such areas still remain in most and Powlesland, 1988; McLennan and districts of the mainland, and they must be McCann, unpublished). Little spotted kiwis preserved in their entirety if kiwis are to also eat a wide range of soil-inhabiting have a good chance of surviving invertebrates (Colbourne, Baird & Jolly, indefinitely. 1990). They may take slightly smaller items The variety of social behaviour among and depend less on aquatic insects than do kiwis also has implications for the the larger kiwis (Hill and Hill, 1987, quoting techniques used to assess kiwi abundance. Richard Henry). The most frequently used technique relies SOCIAL BEHAVIOUR AND on counts of calls, and assume that these DISPERSION originate from territorial pairs. We now In most parts of New Zealand, kiwis are know that this underlying assumption is not both monogamous and territorial. Pairs always appropriate, and techniques will generally form long-lasting bonds which have to be developed which allow for persist for several or more years. Territories variations in social behaviour. vary in size from 1.6 ha to 40 ha, depending BREEDING BEHAVIOUR AND on species and locality, and are defended by BREEDING SUCCESS both members of a pair. All three species of kiwi are K-selected, Two exceptions to this social system in that adults are long-lived and have low have been noted in Northland. Potter (1989) reproductive rates. Average life-spans are found at Tangiteroria that pairs occupied probably about 10 years, with some adults home ranges of about 30 ha, which achieving an age of 30-35 years. Male kiwis overlapped with those of other birds. A are sexually mature at an age of 18 months; little further north at Waitangi, M. Taborsky females do not lay until they are 3-5 years (pers. comm.) observed a complex system. old (Reid & Williams, 1975). Some unpaired males were not territorial All three species have a long breeding and ranged widely, others did hold season, beginning in June or July and territories but these overlapped considerably finishing in February or March. This means with territories of paired birds. Paired birds' that kiwis in the mountains of the South territories hardly overlapped at all with other Island often lay when the soil is frozen and pairs. The most notable departure from the temperatures at night are well below 0°C. normal social system is on Stewart Island, where the birds live in groups of varying Egg Production size and composition (R. Colbourne, pers. Brown kiwis in the North Island comm.). Large groups comprise three to five normally lay two eggs, 20 - 30 days apart, in mature adults, and a similar number of a short burrow dug into the side of a bank or juveniles of various ages. The members of hill. In Tangiteroria (Northland), kiwis groups appear to be related and co-operate seldom re-lay if their first clutch fails, but together to brood chicks, defend their instead wait a year before they try again territories, and possibly share incubation of (Potter, 1989). Females in low density eggs. populations in Hawke's Bay are more The social behaviour of kiwis is such that productive. They replace eggs which fail the birds have a large requirement for space, early in the breeding season, and sometimes irrespective of whether they are living in lay a second clutch after their first one has 1 3 successfully hatched (McLennan, 1988). life, before they are old enough to leave the This means that they often lay four or five nest. Pairs in both Hawke's Bay and eggs in as many months, with a combined Northland fledge 0.3 to 0.5 chicks per year weight similar to that of their own body. (McLennan, 1988; Potter, 1989). Few Little spotted kiwis on Kapiti Island have chicks probably survive the journey to clutches of one or two eggs, and sometimes adulthood, but there is no information on lay twice in a breeding season if their first this. clutch fails (Jolly, 1989). They may also The breeding success of little spotted occasionally lay in autumn. kiwis on Kapiti Island is extremely low at Great spotted kiwis in Northwest Nelson least in some years and localities. Jolly usually lay just one egg a year, irrespective (1989) measured an average production over of whether they are in lowland or upland five years of 0.08 chicks per pair per year in forest (McLennan and McCann, his two study areas. Wekas ate two-thirds of unpublished). Replacement layings are very the kiwi's eggs, and possibly some of their rare, and seem to be achieved only by newly-hatched chicks as well. females which are exceptionally heavy at About 70% of the eggs laid by great the beginning of the breeding season. spotted kiwis in the Saxon and Kahurangi The rate of egg production of the birds areas of Northwest Nelson fail during further south is not known. Nests on Stewart incubation (McLennan and McCann, Island usually contain one egg, as did one unpublished). Invasion by microbes seems found at Okarito in July 1990 (R. to be the main cause of egg loss, followed Colbourne,pers. comm.). by breakage of the eggs by the incubating adults. A few eggs are lost without trace, Incubation possibly to stoats. In the Saxon area, five Males do all of the incubating in the chicks have probably been produced in 21 North Island, but both sexes share the task in pair-years, while at Kahurangi, two chicks the South Island and on Stewart Island have probably been produced in four pair- (McLennan, 1988; Jolly, 1989; Potter, 1989: years. Average production for both McLennan and McCann, 1989; Colbourne, populations is therefore about 0.28 chicks unpublished. ). Little spotted kiwis on Kapiti per pair per year, a little lower than that of Island also have male-only incubation brown kiwis in the North Island. (Jolly, 1989). Incubation takes 70 to 80 days Summary in all species. In summary, kiwis have a low natural Breeding Success breeding success with many eggs lost in About 75% of the eggs laid by brown incubation. This is compounded by some kiwis in the North Island fail to hatch additional loss of eggs to introduced (McLennan, 1988; Potter, 1989). Some are predators. However in most populations, deserted for no apparent reason, some are pairs appear to be producing sufficient invaded by microbes, some are chipped or young to replace themselves every two to cracked by the incubating male, some are eight breeding seasons. This implies the infertile, and a few are eaten by predators, failure of some populations on the mainland probably possums. About half of the chicks is caused by poor adult and/or juvenile that do hatch die in their first three weeks of survival rather than inadequate breeding.

14 7.0

Ability to Recover

Kiwis in large populations have no management, although in practice it might known genetic disorders or inherent not be possible to do this on a large scale. weaknesses that might prevent them from Kiwis have proved to be robust animals responding to management. Those in small, that can be handled and transported with isolated populations face, in addition to the little apparent harm. The North Island usual threats, random processes such as brown kiwis breed regularly in captivity and genetic drift and fluctuations in sex ratio both great and little spotted have done so which can lead to extinction. These too can occasionally. be counteracted by appropriate

8.0

Options for Recovery

OPTION 1: DO NOTHING There have been no attempts yet to All mainland populations of kiwis are manage a population in situ to reverse a either vulnerable or threatened, and decline, mainly because few populations therefore require some action, however have been studied in any detail and the small. The population of little spotted kiwis specific causes of attrition are seldom on Kapiti requires continuing attention until known. In practice, however, it may be at least one other viable population has been difficult to reverse a decline on the established elsewhere. mainland, especially if predators are (as suspected) one of the main causes of it. OPTION 2: MANAGEMENT IN SITU Predator control is currently expensive, The preservation of kiwis on the time-consuming, of short-term benefit, and mainland will depend ultimately on our applicable only on a small scale. However ability to manage them in situ. The rapid developments are being made in this prospects for doing this successfully in the area and improved techniques may soon be immediate future are uncertain: we still available. don't know enough about the status, OPTION 3: TRANSLOCATIONS distribution, size and genetic make-up of most mainland populations to make On many occasions in the past 50 years, informed management decisions. Equally kiwis have been moved from one part of the importantly, we do not have a good country to another, either to remove them understanding of the threats to current from threats (such as land clearance) or to populations which we need to direct increase their numbers and distribution. management effectively. Some of these translocations have

15 succeeded spectacularly, but others have Transfers from the Mainland to the failed dismally, especially those involving Mainland movements between mainland areas. There There have been a number of transfers of is increasing evidence that transfers are North Island brown kiwis within the North more likely to be successful if Island to shift birds threatened by land `behaviourally related' individuals are used clearance. In general these have been (R. Sadleir, pers. comm.) and lack of unsuccessful, probably due to the animals recognition of this may have been a factor in being placed in areas where kiwis have some of the failures. disappeared in the past through causes that Despite the mixed success, translocation are still present, or perhaps to them can be an extremely useful management attempting to `home' to their previous areas. tool, and may have a substantial role to play Transfers from Offshore Islands to the in the future. Mainland Transfers Between Islands This option has not yet been exercised, The option of moving kiwis from one but there are no reasons to think it would not offshore island to another has already been be successful if the threats to the species on exercised on five separate occasions in the the mainland had been addressed. past decade, with the transfer of little spotted OPTION 4: CAPTIVE BREEDING kiwis from Kapiti and D'Urville to other offshore islands. There are indications that Captive breeding and rearing can be this has been successful, though some time either a useful aid to the recovery of some is needed before the establishment of new populations or the last backstop in a self-sustaining populations is confirmed. conservation programme. In the North Island brown kiwi, for example, it is Transfers from the Mainland to Offshore technically possible to remove eggs from Islands some populations, hatch them in captivity, Kiwis have been transferred from the raise the chicks to an age where they are no mainland to offshore islands on numerous longer vulnerable to predators, then return occasions, following Richard Henry's them to the wild. famous attempts to establish viable Such an option is not yet available for populations on Resolution Island at the turn great spotted and little spotted kiwis, nor for of the century. He was unsuccessful then in South Island brown kiwis. Few the case of the little spotted kiwi, but such representatives of these species and sub- transfers have since been crucial to the species are held in captivity, mainly because conservation of this species. the skills for holding and breeding them have not yet been developed.

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