Before a Special Tribunal

Under the Resource Management Act 1991

In the matter of an application for a Water Conservation Order for the Ngaruroro River and Clive River

Statement of Evidence of Rachel Katherine McClellan on behalf of Fish and Game Council, Hawke's Bay Fish and Game Council, Royal Forest and Protection Society of New Zealand, Jet Boating New Zealand, Whitewater NZ Incorporated and Ngāti Hori ki Kohupatiki

19 October 2017

Introduction

1 My name is Rachel McClellan. I am the principal avifauna ecologist with Wildland Consultants Ltd (Wildlands), based in Wellington. I have worked for Wildlands for eight years. I have undertaken avifauna work across New Zealand, including survey and monitoring, assessments of effects, threatened monitoring and management, development of ecological significance criteria, and strategic and restoration plan development and implementation.

2 I have been engaged by Forest and Bird to provide expert evidence on in relation to the application of a Conservation Order for the Ngaruroro River, Hawke's Bay.

3 I visited sites along the length of the upper and lower Ngaruroro River on 3 October 2017.

Qualifications and experience

4 I have the following qualifications and experience:

(a) The degrees of Bachelor of Science in Zoology and Botany from Victoria University.

(b) A Master of Conservation Science (with Distinction). My Masters thesis was on the breeding biology of the Nationally Vulnerable flesh-footed shearwater (Puffinus carneipus) on Karewa Island (Victoria University, 1996).

(c) A PhD in Zoology. My PhD thesis investigated the ecology and management of the Nationally Critical black-billed gull (Larus bulleri) in Southland (University of Otago, 2009).

5 I am a member of the New Zealand Ecological Society and Birds New Zealand (brand name of the Ornithological Society of New Zealand).

6 I have prepared expert evidence for 11 Council and Environment Court hearings addressing issues such as river conservation orders, coastal subdivisions, mining applications, wind farms, hydropower proposals, and council plan changes. Hearings have included the provision of avifauna evidence for the Oreti Conservation Order hearing (for Fish and Game New Zealand), and for Meridian Energy’s North Bank Tunnel proposal on the braided Waitaki River (for the Lower Waitaki River Management Society).

7 I have considerable experience in river bird, seabird and shorebird ecology. I completed my PhD on the Nationally Critical black-billed gull, which examined population trends, the impacts of introduced and native predators, the impact of

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flows on productivity, and the species’ relationship with agricultural ecosystems. Since then, I have remained involved with the monitoring and management of threatened bird species on braided rivers, including providing expert advice for the Department of Conservation’s braided rivers management plan.

8 I also supervised the establishment and ongoing operation of a blue (Hymenolaimus malacorhynchos) protection programme in the Oparara catchment, Kahurangi National Park, while working for the Department of Conservation in 2001-2004. This project has become one of New Zealand’s eight Security Sites for blue duck (I will discuss blue duck management in my main body of evidence).

9 Examples of other projects include: review of the Department of Conservation’s crested penguin (Eudyptes pachyrhynchus) monitoring programme; review of the Yellow-eyed Penguin Trust’s work on yellow-eyed penguins (Megadyptes antipodes) on Rakiura (Stewart Island); avifauna (including seabird) restoration and management components of the Department of Conservation’s Dusky Sound Restoration and Conservation plan, and the Project Janszoon restoration plan for Abel Tasman National Park; restoration plan for Long Point, Catlins, including reintroduction of seabird species including albatross; analysis of population trends of black-billed gulls in the ; aerial surveys of Canterbury rivers for black-billed gulls; and provision of expert evidence on the effects of the Rena wreck on seabirds and shorebirds.

10 While this is not a hearing before the Environment Court, I confirm that I have read the code of conduct for expert witnesses contained in the Environment Court Consolidated Practice Note (2014). I have complied with it when preparing my written statement of evidence and I agree to comply with it when presenting evidence. I confirm that the evidence and the opinions I have expressed in my evidence are within my area of expertise. I have not omitted to consider material facts known to me that might alter or detract from the opinions that I express.

Scope of evidence

11 For the purpose of the Stage 1 hearing of this Water Conservation Order application, I have been directed to provide evidence on birds of the upper Ngaruroro River and its tributaries. The main waterbird of conservation interest in the upper Ngaruroro is the Nationally Vulnerable blue duck. Significant bird habitat and populations also exist in the lower river and these values will be addressed through the Stage 2 hearing. The scope of this statement of evidence is as follows:

(a) Overview of bird habitats of the Ngaruroro catchment;

(b) Relevant surveys and reports of upper Ngaruroro avifauna;

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(c) The bird community of the Ngaruroro catchment;

(d) Blue duck; and

(e) Grey duck.

Bird habitats of the Ngaruroro and its tributaries

12 The Ngaruroro River is one of the North Island’s largest braided rivers1. The river can be divided into four main sections:

(a) The upper reaches of the river above the Whanawhana cableway (and its tributaries) which are mostly single channel. The upper reaches and tributaries flow through steep, rugged country which mostly comprises regenerating indigenous forest and scrub and some commercial pine plantations. The upper Ngaruroro and its many tributaries support the rare blue duck, a specialist species of waterfowl dependent on high quality, fast flowing water.

(b) The reaches between Whanawhana and the Fernhill Bridge which are extensively braided. Hundreds of hectares of bare gravels are available for New Zealand’s specialist braided river bird species, all of which are Threatened or At Risk. This section also includes the only significant freshwater swamp associated with a river in Hawke's Bay2. Pigsty Swamp is an oxbow wetland created by movement of the river away from the location, and is located approximately six kilometres downstream of the Whanawhana cableway.

(c) The reaches below Fernhill, which are more modified and mostly single channel.

(d) The Waitangi Estuary and associated wetlands, including the gravel bars, and the Railway Wetland. A diverse range of bird species are found at this location. Some bird species that roost or breed at this location will forage in the lower Ngaruroro River, just as birds breeding in the lower Ngaruroro River may feed in the estuary and wetlands.

13 This evidence addresses the bird values of the upper Ngaruroro catchment.

1 Wilson G. 2001: National distribution of braided rivers and the extent of vegetation colonisation. Landcare Research Contract Report LC0001/068. Prepared for the Department of Conservation, Twizel. 2 Parrish G.R. 1988: Wildlife and wildlife habitat of Hawke’s Bay rivers. Science & Research Series 2. Department of Conservation, Wellington.

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Relevant surveys and reports of upper Ngaruroro avifauna

14 Many of the reaches of the upper Ngaruroro River above the Whanawhana cableway have never been formally surveyed for birds, including blue duck. In contrast, six bird surveys of the lower Ngaruroro River have been undertaken in the years 1962, 1967, 1972, 1984, 1986, and 1993. A section of the lower Ngaruroro was also surveyed in 2010. However, several of the tributaries of the upper Ngaruroro were specifically surveyed for blue duck in the 1990s, and the blue duck population is now managed in the Ikawatea and Apias tributaries by the Department of Conservation working in partnership with a Maori Land Trust (see paragraphs 31-33).

15 Several assessments of the biodiversity values and, in particular, the bird values of the Ngaruroro have been completed. The first of these was the New Zealand Wildlife Service’s report in 1998 that, in addition to summarising survey results, also assessed the values of four Hawke's Bay rivers using the Sites of Special Wildlife Interest criteria. However, it did not specifically address the upper catchments of the river.

16 The second assessment was done as part of the Protected Natural Areas Programme in 1993, where the surveys assessed remaining natural areas within the Heretaunga Ecological District (including the lower Ngaruroro River, but not the upper catchment).

17 The most recent assessment was undertaken in 2012 using the River Values Assessment System (RiVAS), which applied criteria to assess existing value and potential value of every river in the Hawke's Bay for birds. It assessed the bird values of the upper Ngaruroro catchment separately from the lower Ngaruroro catchment. The RiVAS assessment is discussed in greater detail in paragraphs 55-63.

18 Two recent unpublished reports by independent consultants, Dr Brent Stephenson3 and Dr Richard Seaton4, specifically discuss the bird values of the Ngaruroro River.

19 Lastly, Hawke’s Bay Regional Council has published or commissioned several reports which summarise habitat and fauna values, condition, and management of the Ngaruroro River and its estuary. These include publications relating to the management of water within the Tutaekuri, Ahuriri, Ngaruroro and Karamu

3 Stephenson B.M 2010: Final report – baseline study and assessment of effects on braided riverbed bird communities. Unpublished report, Eco-Vista Photography & Research Ltd. 59p. 4 Seaton R. 2014: Assessment of outstanding avifauna values on the Ngaruroro River. Report prepared for the New Zealand Forest and Bird Protection Society. The Catalyst Group. 13p.

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catchments (or TANK)5, a biodiversity inventory for the region6, and the Ecological Management and Enhancement plan for the Ngaruroro River flood protection and drainage scheme, prepared by MWH7.

The bird community of the Ngaruroro catchment

20 The bird community of the Ngaruroro catchment has been described by two authors, Stephenson (2010) and Seaton (2014), who both include terrestrial birds in their species lists. Dr Stephenson lists 83 bird species that inhabit the upper and lower riverbed, riparian habitats, freshwater wetlands, and the Waitangi Estuary and associated habitats. Dr Seaton lists 93 species that have been recorded from the Ngaruroro catchment since the early 1960s; his list includes some species that are now unlikely to be present (such as brown kiwi). Both authors include birds that are rare visitors to the river and estuary. I provide a combined list of all species in Appendix 1.

21 The combined list contains 58 bird species that are dependent on the river for some stage of their lifecycle. This list includes, for example, seabirds that venture into estuarine habitats such as the Australasian gannet (Morus serrator), shags, herons, oystercatchers, gulls, terns, international migratory waders, and waterfowl. Most of these species are restricted to the estuarine and braided habitats of the lower Ngaruroro River.

22 In contrast, the upper Ngaruroro and its tributaries support fewer species of waterbirds. Species known from the upper Ngaruroro include the blue duck, banded dotterel, pied stilt, and grey duck. Blue duck are well known from the upper Ngaruroro and its tributaries. Suitable habitat for banded dotterel and pied stilt is limited compared to the lower Ngaruroro, and these two species are rare in the upper catchment. Grey duck are present, but it is not known whether they are pure grey duck, or hybrids with the introduced mallard. Blue duck and grey duck are discussed in the following sections.

Blue duck

23 Blue duck (whio) is an endemic species, and a white-water specialist. It has no other close relatives in the world. Only four other species of waterfowl in the world permanently live in fast-flowing water (of 165 waterfowl species). The presence of blue duck is often considered an indicator of the health of a riverine

5 For example, Madaraz-Smith A., Wade O., Wade H. and A. Hicks 2016: The estuaries of the TANK catchments: Ahuriri and Waitangi estuaries. HBRC Report No. RM 16-20. Hawke’s Bay Regional Council, Napier. 6 Hashiba K., Wade O. and W. Hesketh 2016: Hawke's Bay biodiversity inventory: current state of knowledge. HBRC Report No. RM 13/23–4554. Hawke’s Bay Regional Council, Napier. 7 MWH 2011: Ngaruroro River flood protection and drainage scheme – Ecological management and enhancement plan. HBRC Report No. AM 11-04. Prepared for Hawke’s Bay Regional Council, Napier.

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ecosystem, as research has shown that blue duck are dependant on high water quality, stable riverbeds, relatively steep gradients, high proportions of boulders (Plate 1), low transport of fine or suspended sediments, indigenous riparian forest, and high abundance of stoneflies8,9.

Plate 1: Myself and Chippy Wood releasing blue duck with radio-transmitters back into the Oparara River, Kahurangi National Park. A relatively steep gradient and high proportion of boulders is evident. (Department of Conservation, c.2002)

24 Historically, forest clearance reduced the distribution and abundance of blue duck. However, forest clearance in remaining blue duck habitat has largely stopped, and the primary threat now affecting the species is predation by stoats10. Where pest control is absent, populations continue to decline. However, where control of is undertaken, blue duck populations can increase rapidly – doubling or tripling in only a few years11.

8 Collier K.T., Moralee S.J. and Wakelin M.D. 1993: Factors affecting the distribution of blue duck Hymenolaimus malacorhynchos on New Zealand rivers. Biological Conservation 63: 119-126. 9 Glaser A., van Klink P., Elliott G. and Edge K-A. 2010: Whio/blue duck (Hymenolaimus malacorhynchos) recovery plan: 2009-2019. Threatened Species Recovery Plan 62. Department of Conservation, Wellington. 39 p. 10 A.L., Edge K-A., Smart A.F., Hill G.S., and Willans M.J. 2008: Large scale predator control improves the productivity of a rare New Zealand riverine duck. Biological Conservation 141: 2784-2794.

11 Glaser A., van Klink P., Elliott G. and K-A Edge. 2010: Whio/blue duck (Hymenolaimus malacorhynchos) recovery plan: 2009-2019. Threatened Species Recovery Plan 62. Department of Conservation, Wellington. 39 p.

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25 The species remains threatened, and is listed as Nationally Vulnerable, as it is considered to meet the criterion ‘C(1/1)’, defined as a population of 1,000-5,000 mature individuals, that is predicted to decline by 10-50% in the next three generations. Exact numbers are difficult to determine as the habitat in which blue live is often very difficult to access and survey.

26 In the North Island, blue duck are now absent from the Orongorongo, Rimutaka and Tararua Ranges in the south. Blue duck in the Ruahine Ranges represent the southernmost populations in the North Island.

27 The Department of Conservation published a Blue Duck Recovery Plan in 201012. The first priority of the plan was to establish eight ‘Security Sites’ for blue duck throughout the country. Blue duck at these locations are intensively managed to enhance survival and productivity, the aim being to increase the numbers of pairs at each site to a minimum of 50, with an overall target of 400 pairs across the eight sites by 2014.

28 Management includes the trapping of mustelids at all sites, aerial 1080 operations at most sites, and Whio Operation Nest Egg at limited sites (where eggs are taken from the wild into captivity and juveniles released when they are less vulnerable to predation). I have summarised the data from ‘Whio Manager’, the online geospatial database managed by the Department Conservation, which provides up-to-date blue duck observations and trap locations in easily accessible formats. Numbers of pairs located in each Security Site in the 2016-2017 season as reported in ‘Whio Manager’ are as follows:

(a) Northern Te Urewera: 33 pairs;

(b) Whirinaki: 97 pairs;

(c) Tongariro Forest: 138 pairs;

(d) Manganui o te Ao and Retaruke Rivers: 78 pairs;

(e) Oparara-Ugly: 60 pairs;

(f) Wangapeka-Fyfe: 50 pairs;

(g) Central Southern Alps: 17 pairs; and

(h) Northern Fiordland: 28 pairs.

12 Glaser A., van Klink P., Elliott G. and K-A Edge. 2010: Whio/blue duck (Hymenolaimus malacorhynchos) recovery plan: 2009-2019. Threatened Species Recovery Plan 62. Department of Conservation, Wellington. 39 p.

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29 The size of the sites varies markedly, as does the time under management, and the intensity of management, which in part explains the significant differences between the sites. The Recovery Plan’s goal of 400 pairs by 2014 has been exceeded; there are now an estimated 501 pairs under management within the Security Sites (see above), and this total is increasing13.

30 Elsewhere, blue duck are managed at 16 ‘Recovery Sites’ throughout the country. In 2016-2017, 98 pairs of blue duck were recorded across the 16 sites (a mean of just over six pairs per Recovery Site). The Ruahine Ranges is one of these recovery sites, and takes in part of the upper Ngaruroro catchment14.

31 Blue duck are considered to be continuing to decline in areas where no management is occurring.

Blue duck in the upper Ngaruroro catchment

32 A significant amount of work has been undertaken with a portion of the upper Ngaruroro catchment’s blue duck population; the full population has not been surveyed. The earliest work was undertaken by the Department of Conservation, which carried out a banding and monitoring programme of blue duck in the upper Ikawatea Stream between 1991-1997 (particularly the tributaries of the Apias and Mistake Streams).

33 More recently, trapping programmes were established to protect the blue duck populations, both in the upper Ngaruroro catchment, and in catchments to the south and east. The first of these was Te Potae O Awarua, a partnership between the Department of Conservation and the Aorangi/Awarua Trust, which started trapping in 2007. Further trap lines were established in the Apias and Ikawatea subcatchments in 2010, and are checked by volunteers based in Wellington. In total, five different groups (one being the Department of Conservation) maintain the predator control networks in this region of the northern Ruahine Ranges.

34 The Department of Conservation has undertaken dog surveys for blue duck within the trapped areas in 2009-2010 and in 201615,16,17. The results of the surveys are shown in Table 1, and indicate a total of 25 adults in 2009-2010, and

13 BirdLife International. 2016. Hymenolaimus malacorhynchos. The IUCN Red List of Threatened Species 2016: e.T22680121A92844858. 14 Data from ‘Whio Manager’, accessed October 2017.

15 Robson S. 2009: Summary of whio survey Mangatera, Waiokotore and Ikawatea Streams November 2009. Unpublished report. Department of Conservation, Palmerston North. DOCDM-515069. 16 Robson S. 2010: Whio survey Apias 27th-30th November 2010. Unpublished report. Department of Conservation, Palmerston North. 17 Robson S. 2016: Dog whio survey Northern Ruahine December 2016 (Mangatera and Apias Rivers). Unpublished report. Department of Conservation, Palmerston North.

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22 adults in 2016. The low numbers of pairs observed in the Apias in 2010 was thought to be due to late laying as a result of ongoing flooding during the breeding season; females may have still been on nests rather than in the water with their broods (Robson 2010).

Table 1: Blue duck numbers recorded from Department of Conservation surveys, 2009-2010 and 2016.

Waterway Year Number of Birds Total adults Ikawatea Nov. 2009 6 pairs, 1 adult, 15 ducklings 13 Apias Nov. 2010 2 pairs, 8 adults, no ducklings 12 Ikawatea Nov. 2016 4 pairs, 3 adults, 6 ducklings 11 Apias Dec. 2016 3 pairs, 5 adults, 6 ducklings 11

35 Mr John Cheyne (formerly of the Fish and Game Council, the Department of Conservation, and also the New Zealand Wildlife Service, Hawke's Bay) has considerable knowledge of the catchment’s blue duck population from several decades of work and recreational hunting and fishing in the area. He was involved in the Department of Conservation’s banding programme in the Ikawatea during the 1990s.

36 Mr Cheyne was asked for estimates of blue duck populations in relation to the application of the River Values Assessment System to rivers in the Hawke's Bay some five years ago. He provided an estimate for the upper Ngaruroro of 20-30 birds, which has also been used in the application for this Water Conservation Order. However, he considered that this estimate was made in haste, and without a thorough evaluation of tributaries, and did not take into account the recent management in the Ikawatea.

37 Mr Cheyne has updated this estimate, using his extensive knowledge of the waterways and what constitutes suitable blue duck habitat, historical Department of Conservation reports (written prior to the reports summarised below), and past and recent observations of blue duck, both his and others. His report describing the catchment’s blue duck population is attached as Appendix B. A summary of his estimate of the blue duck population within the upper Ngaruroro catchment is provided at Table 2.

Table 2: Estimated blue duck numbers in the upper Ngaruroro catchment (J. Cheyne 2017; see Appendix B).

Waterway Details Number of Birds Ikawatea Stream Apias, Mistake 14 Ikawatea above forks 4 Ikawatea below forks 2 Makirikiri 4 Taruarau Stream 10 Koau Stream 4 Ngaruroro River Including tributaries; source 12 to Taruarau confluence Total 50

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38 Mr Cheyne’s estimates from the Ikawatea, Apias, Mistake and Makirikiri closely align with the Department of Conservation surveys of the same waterways in 2009-2010 (24 birds compared to 25 and 22 birds found by the Department of Conservation). Mr Cheyne’s estimates also include other waterways within the upper Ngaruroro catchment with which he is familiar that have never been formally surveyed for blue duck. He considers that approximately 50 birds are present in the upper Ngaruroro catchment, mostly within the Ikawatea-Apias, where management is being undertaken.

39 Stephen (Nobby) Robson of the Department of Conservation (Biodiversity Supervisor, and supervisor of the Ruahine Recovery Site) considers that blue duck are dispersing from the managed sites into other unmanaged catchments, given observations of the species in adjacent waterways where it has not been observed for years (S. Robson pers. comm. Oct 2017).

40 In my opinion, given the estimates above in Tables 1 and 2, and given the small size of most of the populations protected within Recovery Sites (paragraph 30, the blue duck population of the upper Ngaruroro catchment is likely to represent a stronghold for the species.

Ramsar assessment of the upper Ngaruroro River

41 The Ramsar Convention was established to encourage nations to work towards the conservation and wise use of the world’s wetlands. The treaty was negotiated during the 1960s, and adopted in the Iranian city of Ramsar in 1971. Contracting Parties, of which New Zealand is one (becoming a party to the Convention in 1976), commit to work towards the wise use of all their wetlands, and to designate suitable wetlands for the list of Wetlands of International Importance (Ramsar List) and ensure their effective management.

42 As of the end of 2016, 169 countries were contracting parties18. As of 8 June 2015, 2,208 Ramsar sites covering 210 million hectares have been listed19. Within New Zealand, six sites have been listed to date; Whangamarino, Waikato; Kopuatai Peat Dome, Waikato; Firth of Thames, Waikato; Manawatu River Estuary, Manawatu; Farewell Spit, Nelson; and Awarua Wetland/Waituna Lagoon, Southland. Other sites are likely to be added in the future20 Potential candidates for the Ramsar Convention’s list of Wetlands of International Importance are assessed against eight criteria. Several criteria are relevant to bird populations, and are listed below:

18 http://www.ramsar.org/sites/default/files/documents/library/annotated_contracting_parties_list_e.pdf 19 The Ramsar Convention 2015: The 4th Strategic Plan 2016-2024. Adopted by the 12th Meeting of the Conference of the Parties at Punta del Este, Uruguay, 1-9 June 2015. 20 I co-authored a management plan in June for the Avon-Heathcote Estuary/Ihutai for a Trust that intends to use the plan to seek Ramsar status for the Christchurch estuary and oxidation ponds.

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(a) Criterion 2: A wetland should be considered internationally important if it supports vulnerable, endangered, or critically or threatened ecological communities.

(b) Criterion 3: A wetland should be considered internationally important if it supports populations of plant and/or species important for maintaining the biological diversity of a particular biogeographic region.

(c) Criterion 4: A wetland should be considered internationally important if it supports plant and/or animal species at a critical stage in their life cycles, or provides refuge during adverse conditions.

(d) Criterion 5: A wetland should be considered internationally important if it regularly supports 20,000 or more water birds.

(e) Criterion 6: A wetland should be considered internationally important if it regularly supports 1 percent of the individuals in a population of one species or subspecies of water bird.

43 Evaluation using Ramsar criteria is an internationally recognised method to assess the biodiversity values of wetlands across the globe. The criteria provide a consistent and robust method for assessing the international importance of wetlands including rivers. In my opinion, it is more appropriate to assess the Ngaruroro river as a whole against the Ramsar criteria, most importantly because each of the main habitat types within the river – the upper forested channels, the lower braids, and the estuary – each have unique bird values. Considered together and assessed against the Ramsar criteria, these combined values demonstrate the overall importance of the river to birds much more accurately than considering each of the main habitat types separately.

44 Nevertheless, for the purposes of this hearing, I have assessed the upper Ngaruroro and its tributaries separately. In my opinion, the upper Ngaruroro and its tributaries meet Ramsar criteria 2, 4 and 6.

45 The Department of Conservation has published national guidelines for the assessment of potentially internationally significant wetlands in New Zealand21, and I have used this guide to assess how well the criteria are met in regard to the upper catchment (the guidelines use the following terminology for each criterion: ‘Strongly’, ‘Moderately’, and ‘Slightly’ met).

46 The guidelines state that Criterion 2 is strongly met if the wetland is “Natural or near-natural habitat for a population of one or more species that are Nationally

21 Denyer, K.; Robertson, H. 2016: National guidelines for the assessment of potential Ramsar wetlands in New Zealand. Department of Conservation, Wellington. 58 p.

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Critical or Nationally Endangered”, and moderately met if the wetland is “Natural or near-natural habitat for one or more species that are Nationally Vulnerable”.

47 Interestingly, the Department of Conservation guidelines use the New Zealand threat classification categories of Nationally Critical, Nationally Endangered, and Nationally Vulnerable, rather than the international IUCN Red List categories Critically Endangered, Endangered, and Vulnerable, which would normally be used for a Ramsar assessment. The authors state that this is because for some taxon groups, such as , the international classifications can be significantly out-of-date.

48 However, in the case of New Zealand birds, the IUCN Red List is very current; the blue duck assessment was undertaken last year, and peer-reviewed by the Department of Conservation22. The international classification for blue duck is Endangered, in contrast to DOC’s current national classification of Nationally Vulnerable. According to Department of Conservation guidelines, Criterion 2 is therefore moderately met by the upper Ngaruroro. However, in my opinion, there is justification for considering it strongly met given the more-up-to-date international threat classification of blue duck.

49 The guidelines state that Criterion 4 is strongly met by “Wetlands that are demonstrated to be key habitats and national strongholds for threatened indigenous wetland-dependent species during breeding, migration, moulting or weather extremes”. Blue duck is a threatened (both nationally and internationally), wetland-dependant species, and the upper Ngaruroro catchment is likely to be a national stronghold (see Criterion 6, and paragraph 40).

50 Criterion 6 identifies wetlands that regularly support 1% or more of a waterbird population. Good justification exists for treating the North and South Island populations separately. Two genetics studies have demonstrated the genetic differentiation of the North and South Island populations, and the split is also recognised by the ‘Waterbird Population Estimates’ (WPE) online database23. The Department of Conservation recognises this distinction, and maintains the two populations as separate management units24.

51 The most recent publication of blue duck population estimates is the BirdLife International/IUCN 2016 blue duck evaluation, which was peer-reviewed by the

22 BirdLife International. 2016. Hymenolaimus malacorhynchos. The IUCN Red List of Threatened Species 2016: e.T22680121A92844858. 23 http://wpe.wetlands.org/ This database provides current and historic estimates, trends and 1% thresholds for over 800 waterbird species and 2,300 biogeographic populations worldwide, in part to support the work of the Ramsar Convention. 24 Robertson B.C., Paley R. and Gemmell N.J. 2003: Broad-scale genetic population structure in blue duck Hymenolaimus malacorhynchos: Pilot study of mitochondrial genetic variation. DOC Science Internal Series 115. Department of Conservation, Wellington. 12 p

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Department of Conservation25. This provides an estimate of 640 pairs on the North Island and fewer than 700 pairs on the South Island, combining to give a total population of between 2,000 and 3,000 birds26.

52 Assuming a population of 640 pairs or 1,280 birds in the North Island, the 1% threshold is therefore 13 birds, and the 5% threshold is 64 birds.

53 The upper Ngaruroro catchment clearly supports more than 1% of the North Island population of blue duck (and also supports more than 1% of the national population). The population of 50 blue duck in the upper Ngaruroro represents 3.9% of the North Island population of 1,280 birds. According to the Department of Conservation guidelines, Criterion 6 is moderately met by a wetland that “Regularly supports 2-24% of a biogeographical population of one of more waterbird species or subspecies”.

54 In summary, I consider that the upper Ngaruroro and its tributaries meet three Ramsar criteria that define a wetland of international significance, and that these criteria are moderately to strongly met because of the presence of a significant population of blue duck.

RiVAS assessment of the upper Ngaruroro catchment

55 The ecological significance of bird populations of the upper Ngaruroro catchment was formally assessed using the RiVAS in 2012. New information on the blue duck population in the Ngaruroro, and recent genetic research on the species, means that it is appropriate to re-assess the upper Ngaruroro using the RiVAS.

56 The Hawke’s Bay RiVAS application assessed the lower and upper Ngaruroro catchments along with 11 other river systems or ‘grouping’ of rivers (37 waterways in total)27. The assessment method is intended to provide a means to inform decision-makers of the significance of particular values of a river, using a consistent approach, with mostly objectively-assessed criteria. One of the first sets of river values assessment criteria to be developed was for indigenous bird communities. The primary attributes of each river that are assessed for birds are:

(a) Relative distinctiveness (subjective; how widely is the habitat type or species assemblage distributed elsewhere in New Zealand);

25 Andrew Glaser, pers. comm. Sept. 2017 (Department of Conservation Blue Duck Recovery Group Leader). 26 BirdLife International. 2016. Hymenolaimus malacorhynchos. The IUCN Red List of Threatened Species 2016: e.T22680121A92844858. 27 Hughey K.F.D., Cameron F., Cheyne J., Dickson R., Forbes A., Hashiba K., Rook H., Sharp T., Stephenson B. and Welch B. 2012: Native birdlife in Hawke’s Bay: Application of the River Values Assessment System (RiVAS and RiVAS+). Lincoln University, New Zealand.

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(b) Amount of habitat (objective; measured in area for braided rivers and distance for single channel rivers);

(c) Numbers of birds (objective28);

(d) Foraging guilds (objective; ranges from 0 to 8 foraging guilds29);

(e) Number of Threatened or At Risk bird species present (objective30); and

(f) Proportion of Threatened or At Risk bird species present with a significant proportion of their total populations (i.e. >1% or >5%; objective or subjective).

57 These six attributes are then each given a score, which is then summed. In the case of the Hawke's Bay assessment, the summary scores were ranked. Rivers where a species exceeds 5% of the national population are immediately considered nationally significant, regardless of score, “as this level has been used in a number of Water Conservation Order decisions as being a threshold for national importance (despite the fact that the World Conservation Union (IUCN) uses a 1% level for international significance)”31. National significance is also given to those rivers that have a total score of 15 or more across all attributes.

58 The assessment split the Ngaruroro into the upper river and lower river (at the Whanawhana cableway). The upper river ranked fifth of the 37 Hawke's Bay waterways that were assessed. This assessment listed blue duck, banded dotterel and pied stilt as present. Blue duck was noted as increasing in numbers and, based on Mr Cheyne’s estimate of 20-30 blue duck, the population met the 1% threshold assessed against a total national population, including North and South Island birds, of 3,000 individuals.

59 As I have described in paragraph 50, the North and South Island populations of blue duck are treated as separate units by the Department of Conservation (supported by genetics research). Using the North Island population as a reference, and Mr Cheyne’s updated estimate of 50 blue duck, this further

28 Hughey et al. (2012) adjusted the total number of birds by subtracting the number of southern black- backed gulls present. The gull is a native species, but has undergone a population explosion due to human activities, and is often considered a pest. It is often more numerous on rivers than all other waterbird species combined, and is a poor measure of the significance of a waterway to birds. 29 For example, guilds include open water divers (like shags), deep water waders (such as oystercatchers, stilts and herons), shallow water waders (like dotterels), and torrent specialists (like blue duck). 30 Hughey et al. (2012) did not include Australasian bittern or grey duck in their evaluation. Bittern were considered too cryptic, and grey duck too difficult to accurately identify. 31 Hughey K.F.D., Cameron F., Cheyne J., Dickson R., Forbes A., Hashiba K., Rook H., Sharp T., Stephenson B. and Welch B. 2012: Native birdlife in Hawke’s Bay: Application of the River Values Assessment System (RiVAS and RiVAS+). Lincoln University, New Zealand.

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reinforces this exceedance of the 1% threshold, but does not meet the 5% threshold of 64 birds.

60 However, the RiVAS has a second complimentary assessment system, RiVAS+, which takes into account potential interventions which could be used to enhance river values. Interventions can include means such as enhancing water quality (by removing stock), removing fish barriers, and enhancing flows. The RiVAS+ methodology calls for the assessment panel to select the two most important interventions for each river, noting that these interventions need to be practical and feasible, rather than ideal. However, Hughey et al. (2012) does not specify which interventions were considered for each river or section of river as part of their assessment.

61 One of the example interventions listed in the Hawke's Bay assessment is pest control to improve riparian habitat. I note, however, that the Hughey et al. (2012) report does not list an intervention that involves pest control to improve productivity and survival of river bird populations. Perhaps this is because such pest control operations may not be generally considered ‘practical’ or ‘feasible’, but rather, ‘ideal’. Large scale pest control operations to protect braided river bed birds, for example, are hugely expensive, and can have mixed results.

62 However, low intensity trapping operations (such as a single line of traps every 100-200 m along one side of a river) are known to be successful at increasing blue duck populations. The volunteer trapping programme in the Ikawatea and tributaries demonstrates the feasibility of such programmes.

63 In my opinion, further stoat control in other parts of the upper Ngaruroro and its tributaries would be likely to increase the population of blue duck in the upper Ngaruroro catchment past the 5% threshold of 65 birds within a relatively short period of time. Accordingly under a RiVAS+ assessment, I consider that the upper Ngaruroro catchment would be considered nationally significant, regardless of its regional ranking as assessed by Hughey et al. (2012).

Comparison with other rivers protected by Water Conservation Orders

64 Thirteen rivers are protected by Water Conservation Orders. Two of the rivers, Manganui o te Ao River and the Buller River, are considered to have outstanding blue duck values; that is, their respective blue duck populations are an outstanding feature as written in legislation. The two Water Conservation Orders contrast markedly in their treatment of blue duck or blue duck habitat as an outstanding feature. The thresholds of 1% or 5% were not used to assess the importance of either river catchment for blue duck.

65 The Manganui o te Ao River received a Water Conservation Order in 1989 (the following is taken from the Order, paragraph 3):

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(a) It is hearby declared that the Manganuioteao River and its tributaries, the Mangaturuturu and Makatote Rivers, and the Waimarino and Orautoha Streams, include and provide for---

(i) Outstanding wild and scenic characteristics;

(ii) An outstanding wildlife habitat for the blue duck or whio (Hymenolaimus malacorhynchos); and

(iii) An outstanding recreational fishery.

66 The blue duck population of the Manganui o te Ao River was one of the earliest to be intensively studied in New Zealand. Surveys of the catchment began in 1979, and blue ducks were monitored and banded in a 9.3 kilometre section of the river for at least 10 consecutive years32. In 1987, shortly before the Water Conservation Order was legislated, a full survey of the Manganui o te Ao catchment found 36 pairs of blue duck, and 122 blue duck in total (including unpaired adults and juveniles), making it one of the largest breeding populations of blue duck within the North Island33,.

67 Wildlife experts presented this survey data to the committee of the National Water and Soil Conservation Authority as part of the application for the Manganui o te Ao River Water Conservation Order. The report of the National Water and Soil Conservation Authority noted that the national blue duck population was estimated to be 2,000-4,000 birds, and that most river populations consisted of less than 50 birds. The authority’s decision that the river provided outstanding habitat for blue duck was based on the size and density of the blue duck population, and the quality of the habitat in the catchment34.

68 The Buller River received a Water Conservation Order 2001. In comparison to the Manganui o te Ao, the Buller River Water Conservation Order covers numerous streams, creeks, rivers and lakes, it being one of the largest, ummodified river catchments in New Zealand. As legislated, blue duck is noted as an outstanding feature in only a few locations within the catchment, specifically:

(a) Maruia River and all tributaries upstream of Alfred River confluence;

(b) Blackwater River and Ohikaiti River;

32 Williams 1990: Minutes of the 2nd annual meeting of the Blue Duck Liaison Group. Science and Research Internal Report No. 89. Department of Conservation, Wellington. 55p. 33 Williams 1991: Social and demographic characteristics of blue Duck Hymenolaimus malacorhynchos. Wildfowl 42: 65-86. 34 National Water and Soil Conservation Authority 1988: Report on the Manganuioteao River National Water Conservation Order application. Dated 4 March 1988. National Water and Soil Conservation Authority, Wellington. 20p.

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(c) Ohikanui River and all its tributaries; and

(d) Fyfe River, Sandstone Creek, Johnstons Creek, Brewery Creek and their tributaries.

69 However, in contrast, the Tribunal’s decision on the Buller River Conservation Order application gives very limited details of the blue duck populations. For example, it states “Many forested tributary streams provide habitat for the threatened blue duck”, and the decision does not specifically list blue duck as an outstanding feature35.

70 It is not clear what basis was used for determining the importance of the above waterways (paragraph 61, a-d) for blue duck. For example, the Department of Conservation website notes that blue duck were “rediscovered” in the Maruia Valley in 200336, and further, the Fyfe River blue duck population only numbered two pairs in 200637. Both populations are now managed, and are illustrations of blue duck populations that would likely have been extirpated without intervention.

Grey duck

71 Grey duck is one of New Zealand’s most threatened bird species, and is listed as Nationally Critical. It is found widely through Australia and New Zealand, but is threatened with extinction in both countries through extensive hybridisation with the introduced mallard. Determining whether a bird being observed is a pure grey duck or a hybrid grey/mallard may no longer be possible. A recent publication considered that the quantitative assessment of grey-mallard hybridisation based on the physical appearance of birds (that is, their plumage characteristics) alone was conjectural38.

72 It is possible that isolated populations of grey duck have not yet hybridised. However, this will not be known until extensive genetic work is undertaken nationwide to examine the magnitude of hybridisation. Until then, we cannot be certain that a bird that appears to be a grey duck at any location within New Zealand is actually the Nationally Critical species, or a hybrid. The hybrid form is

35 Ministry for the Environment 1989: Buller River National Water Conservation Order application. Decision of the tribunal appointed by the Minister for the Environment to determine the application. Dated July 1989. 46p. 36 http://www.doc.govt.nz/our-work/te-maruia-waka-huia/blue-duck-whio-in-the-upper-maruia-valley/ Downloaded 15 October 2017. 37 https://faunarecovery.org.nz/whioblue-duck/ Downloaded 15 October 2017.

38 Williams M. and Basse B. 2006: S33-3 Indigenous gray ducks, Anas superciliosa, and introduced mallards, A. platyrhynchos, in New Zealand: processes and outcome of a deliberate encounter. Acta Zoologica Sinica 52 (Supplement): 579-582.

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now so commonplace it has been given its own classification of Not Threatened in the latest iteration of threat classifications for birds.

73 Grey duck has been given the threat classification of Nationally Critical, based on the criterion ‘B(1/1)’, defined as a population of 250-1,000 mature individuals, and a predicted decline of 50-70% in 10 years or three generations, which ever is longer. The population estimate is likely to have very low confidence; numbers could be considerably lower or higher. Nevertheless, assuming a population of 1,000 mature individuals, the 1% threshold for grey duck would be 10 birds.

74 Grey duck are known from the upper Ngaruroro catchment. It is possible that grey duck in the upper Ngaruroro catchment may be sufficiently isolated that resident birds have not hybridised with mallard. However, until an extensive, New Zealand-wide genetic assessment is undertaken it is not possible to say which, if any, areas of New Zealand are of particular importance for grey duck. Accordingly, I have not assessed grey duck further as part of my evidence.

Conclusion

75 The waterways of the upper Ngaruroro catchment support a significant population of the Nationally Vulnerable blue duck. Department of Conservation surveys in the Ikawatea, Apias, Mistake and Makirikiri tributaries in 2009-2010 and 2016 indicate a population of some 22-25 blue duck. Estimates from other waterways in the catchment suggest that the total population may number approximately 50 blue duck. This is comparable to the populations protected within two of New Zealand’s eight blue duck Security Sites, and considerably more blue duck than many of the 15 other Recovery Sites. It is likely that the upper Ngaruroro blue duck population constitutes a national stronghold.

76 I assessed the upper Ngaruroro catchment using internationally recognised Ramsar criteria for the identification of wetlands of international significance, using only its avifauna values. The upper Ngaruroro clearly meets several Ramsar criteria on the basis of its blue duck population alone, including supporting more than 1% of the North Island population of blue duck. As such, the river would warrant application for Ramsar status as a wetland of international significance.

77 I also re-assessed the upper Ngaruroro catchment using the River Values Assessment System, and a second complimentary assessment system, RiVAS+, which takes into account potential interventions which could be used to enhance river values. I consider that it is very likely that further pest management on waterways that are presently unmanaged will increase the blue duck population past the 5% threshold (that is, 65 blue duck from a total of 1,280 North Island blue duck). Under the RiVAS+ method, this would immediately give the upper Ngaruroro catchment national significance.

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78 The upper Ngaruroro catchment is likely to support a smaller population than the Manganui o te Ao catchment, but may support a larger population than the Buller River catchment. Both these catchments have received Water Conservation Orders and are noted as having outstanding blue duck populations and/or habitat.

79 I consider the upper Ngaruroro catchment would qualify as ‘Outstanding’ given it meets criteria for an internationally significant wetland, and given further pest control would be likely to enhance the blue duck population beyond the 5% threshold sometimes used as a criterion for an outstanding feature for previous Water Conservation Orders..

Rachel McClellan 19 October 2017

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Appendix 1: Bird species recorded in the Ngaruroro Catchment (from Stephenson 2010; Seaton 2013, Birds New Zealand unpublished data)

Common Name Species Name Threat Classification Presence Location (Robertson et al. 2017)39 Australasian bittern Botaurus poiciloptilus Nationally Critical Rare, resident Estuary, wetlands Black-billed gull Larus bulleri Nationally Critical Uncommon, regular Estuary, lower river Grey duck Anas superciliosa Nationally Critical Rare, resident? Estuary, river New Zealand shore plover Thinornis novaeseelandiae Nationally Critical Rare, infrequent Estuary White heron Ardea modesta Nationally Critical Rare, infrequent Estuary, lower river Black-fronted tern Chlidonias albostriatus Nationally Endangered Common, regular Estuary Reef heron Egretta sacra sacra Nationally Endangered Rare, infrequent Estuary Banded dotterel Charadrius bicinctus bicinctus Nationally Vulnerable Abundant, regular Estuary, river Blue duck Hymenolaimus malachorhynchos Nationally Vulnerable Uncommon, resident Upper river Caspian tern Hydroprogne caspia Nationally Vulnerable Uncommon, regular Estuary Lesser knot Calidris canutus rogersi Nationally Vulnerable Rare, infrequent Estuary Anarhynchus frontalis Nationally Vulnerable Rare, infrequent Estuary, lower river Banded rail Gallirallus philippensis assimilis At Risk-Declining Rare, unknown Wetland Eastern bar-tailed godwit Limosa lapponica baueri At Risk-Declining Rare, infrequent Estuary Marsh crake Porzana pusilla affinis At Risk-Declining Rare, regular Estuary New Zealand pipit Anthus novaeseelandiae novaeseelandiae At Risk-Declining Common, regular Estuary, river North Island fernbird Bowdleria punctata vealeae At Risk-Declining Uncommon, resident Estuary, wetlands Red-billed gull Larus novaehollandiae scopulinus At Risk-Declining Common, regular Estuary Spotless crake Porzana tabuensis tabuensis At Risk-Declining Rare, regular Estuary, wetlands South Island pied oystercatcher Haematopus finschi At Risk-Declining Uncommon, regular Estuary, lower river White-fronted tern Sterna striata striata At Risk-Declining Abundant, regular Estuary New Zealand dabchick Poliocephalus rufopectus At Risk-Recovering Uncommon, regular Estuary Northern Charadrius obscurus aquilonius At Risk-Recovering Rare, infrequent Estuary, wetlands Variable oystercatcher Haematopus unicolor At Risk-Recovering Rare, regular? Estuary Black-fronted dotterel Elseyornis melanops At Risk-Naturally Uncommon Abundant Estuary, lower river Black shag Phalacrocorax carbo novaehollandiae At Risk-Naturally Uncommon Uncommon, regular Estuary, river Little black shag Phalacrocorax sulcirostris At Risk-Naturally Uncommon Uncommon, regular Estuary, river Royal spoonbill Platalea regia At Risk-Naturally Uncommon Rare, infrequent Estuary Australasian gannet Morus serrator Not Threatened Uncommon, regular Estuary Anas rhynchotis Not Threatened Uncommon, infrequent Estuary, river Black Cygnus atratus Not Threatened Rare, infrequent Estuary

39 Common names, species names, and classifications from Robertson H.A., Baird K., Dowding J.E., Elliott G.P., Hitchmough R.A., Miskelly C.M., McArthur N., O’Donnell C.F.J., Sagar P.M., Scofield R.P. and Taylor G.A. 2017: of New Zealand birds, 2016. New Zealand Threat Classification Series 19. Department of Conservation, Wellington. 23 p.

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Common Name Species Name Threat Classification Presence Location (Robertson et al. 2017)39 Grey teal Anas gracilis Not Threatened Rare, infrequent Estuary, river Little shag Phalacrocorax melanoleucos brevirostris Not Threatened Rare, infrequent Estuary New Zealand kingfisher Todiramphus sanctus vagans Not Threatened Common, regular Estuary, river Paradise Tadorna variegata Not Threatened Abundant Estuary, river Pied stilt Himantopus himantopus leucocephalus Not Threatened Abundant Estuary, lower river Pukeko Porphyrio melanotus melanotus Not Threatened Common, regular Estuary, lower river Southern black-backed gull Larus dominicanus dominicanus Not Threatened Abundant Estuary, lower river Stictocarbo punctatus punctatus Not Threatened Rare, infrequent Estuary Spur-winged plover Vanellus miles novaehollandiae Not Threatened Abundant, resident Estuary, river White-faced heron Egretta novaehollandiae Not Threatened Uncommon, resident Estuary, river Arctic skua Stercorarius parasiticus Migrant Rare, infrequent Estuary Curlew sandpiper Calidris ferruginea Vagrant Rare, infrequent Estuary Eastern cattle egret Ardea ibis coromanda Migrant Rare, infrequent Estuary Eastern little tern Sternula albifrons sinensis Migrant Rare, infrequent Estuary Gull-billed tern Gelochelidon nilotica Vagrant Rare, infrequent Estuary Pacific golden plover Pluvialis fulva Migrant Rare, infrequent Estuary Red-necked stint Calidris ruficollis Migrant Rare, infrequent Estuary Sharp-tailed sandpiper Calidris acuminata Migrant Rare, infrequent Estuary Siberian tattler Tringa brevipes Migrant Rare, infrequent Estuary Terek sandpiper Tringa cinerea Migrant Rare, infrequent Estuary Turnstone Arenaria interpres Migrant Rare, infrequent Estuary White-winged black tern Chlidonias leucopterus Migrant Rare, infrequent Estuary Intermediate egret Ardea intermedia Vagrant Rare, infrequent Estuary Little egret Egretta garzetta immaculata Vagrant Rare, infrequent Estuary Pectoral sandpiper Calidris melanotos Vagrant Rare, infrequent Estuary Canada Branta canadensis Introduced and Naturalised Uncommon, infrequent River Mallard Anas platyrhynchos Introduced and Naturalised Common Estuary, river Apteryx mantelli At Risk-Declining Terrestrial North Island Acanthisitta chloris granti At Risk-Declining Terrestrial Petroica longipes At Risk-Declining Terrestrial Whitehead Mohoua albicilla At Risk-Declining Terrestrial Red-crowned parakeet Cyanoramphus novaezelandiae novaezelandiae At Risk-Relict Terrestrial Long-tailed cuckoo Eudynamys taitensis At Risk-Uncommon Terrestrial Bush falcon Falco novaeseelandiae ferox At Risk-Recovering Terrestrial, river North Island kaka Nestor meridionalis septentrionalis At Risk-Recovering Terrestrial Bellbird Anthornis melanura Not Threatened Terrestrial Gerygone igata Not Threatened Terrestrial Kereru Hemiphaga novaeseelandiae Not Threatened Terrestrial

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Common Name Species Name Threat Classification Presence Location (Robertson et al. 2017)39 Morepork Ninox novaeseelandiae novaeseelandiae Not Threatened Terrestrial North Island fantail Rhipidura fuliginosa placablis Not Threatened Terrestrial Pied Petroica macrocephala toitoi Not Threatened Terrestrial Shining cuckoo Chrysococcyx lucidus lucidus Not Threatened Terrestrial Zosterops lateralis lateralis Not Threatened Terrestrial Swamp harrier Circus approximans Not Threatened Terrestrial, river Prosthemadera novaeseelandiae novaeseelandiae Not Threatened Terrestrial Welcome swallow Hirundo neoxena neoxena Not Threatened Terrestrial, river Yellow-crowned parakeet Cyanoramphus auriceps Not Threatened Terrestrial Australian magpie Gymnorhina tibicen Introduced and naturalised Terrestrial California quail Coturnix novaezelandiae Introduced and naturalised Terrestrial Chaffinch Fringilla coelebs Introduced and naturalised Terrestrial Common blackbird Turdus merula Introduced and naturalised Terrestrial Common myna Acridotheres tristis Introduced and naturalised Terrestrial Common pheasant Phasianus colchicus Introduced and naturalised Terrestrial Common redpoll Carduelis flammea Introduced and naturalised Terrestrial Common starling Sturnus vulgaris Introduced and naturalised Terrestrial Hedge sparrow Prunella modularis Introduced and naturalised Terrestrial European goldfinch Carduelis carduelis Introduced and naturalised Terrestrial European greenfinch Carduelis chloris Introduced and naturalised Terrestrial Feral or greylag goose Anser anser Introduced and naturalised Terrestrial House sparrow Passer domesticus Introduced and naturalised Terrestrial Rock or feral pigeon Columba livia Introduced and naturalised Terrestrial Rook Corvus frugilegus Introduced and naturalised Terrestrial Skylark Alauda arvensis Introduced and naturalised Terrestrial Song thrush Turdus philomelos Introduced and naturalised Terrestrial Yellowhammer Emberiza citrinella Introduced and naturalised Terrestrial

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Appendix 2: Blue duck numbers in the Ngaruroro Catchment

Prepared by John Cheyne, October 2017

The WCO application quotes the Ngaruroro River blue duck population as 20-30 birds (John Cheyne Fish and Game pers comm). I provided this estimate about five years ago. Since that time I have managed to locate some old DOC staff reports (1991-96) on the blue duck banding and monitoring programme carried out in the Ikawatea Stream catchment which provide more substantial information on the population. I participated in this programme as a DOC staff member. In addition I have trout fished and hunted on a number of occasions over the last 30 years in the Ikawatea catchment and adjacent catchments and observed blue duck. I have also talked to a number of other hunters and anglers who have observed blue duck in the areas.

I do not have any personal observations of blue duck in the main Ngaruroro River catchment above the confluence with the Taruarau Stream but I have spoken to a number of hunters, kayakers and rafters that have observed birds in this stretch of water over the last 4-5 years. DOC staff may have carried out a brief survey 10-15 years ago.

Of particular note is the apparent benefit to blue duck of a volunteer lead stoat control trapping programme in the upper Ikawatea-Apias Stream area. This programme has been operating for approximately 5-6 years and birds are now being seen regularly on waters like the Taruarau River where they had not been seen for over 20 years. A pair has bred above the Taihape-Napier Road bridge for the last two years and other birds sighted both upstream and downstream of this point.

It should be noted that significant lengths of stream in the Ngaruroro catchment are extremely rough with many gorges and water falls making them inaccessible which therefore makes it extremely difficult to survey for blue duck.

Different blue duck survey techniques provide different results. The DOC, Napier banding and monitoring programme (1991-97) in the upper Ikawatea Stream, particularly the Apias and Mistake Streams, used three techniques which are complementary. These techniques were used on the regular 4-5 day visits carried out in October and February each year. A certified blue duck dog and handler were not always available. The surveys involved day time walk through without a dog, day time walk through with a dog, and evening and night time spotlighting effort. Generally in these waters approximately one third of the birds were located during a daytime walk through without a dog, another third during a daytime walk through with a dog, and another third by spotlighting at night. During the day some birds roosted up very small side streams (Blind Creek, Red Metal Creek etc.) often above waterfalls and only used the accessible sections of the Apias and Mistake Streams at night. Generally the three methods were required if close to 100% of the resident population was to be located.

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Using the above information sources I now estimate the population of adult blue duck in the Ngaruroro River catchment to be 56 birds which is higher than the 20-30 birds previously quoted. Current estimate by sub catchment is as follows:

 Ikawatea Stream: Apias/Mistake 14, Upper Ikawatea above forks 4, Lower Ikawatea 2, Makirikiri 4 Total 24  Taruarau River 10 Total 10  Koau Stream 4 Total 4  Ngaruroro River and tributaries (source to Taruarau confluence) 12 Total 12

Grand Total 50

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