conservation of the north island brown kiwi (apteryx mantelli

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    Conservation of the North Island Brown Kiwi (Apteryx mantelli):

    current approaches, the successes and limitations, and proposals to

    ensure long term continuity.

    Jack Keast, Tara Kelly, Hayden Moorhouse, Jonathan Tan, & Shih-Yun Wei (2010)

    School of Biological Sciences

    Victoria University of Wellington, Wellington 6012, New Zealand


    The kiwi (Apteryx spp.) is from an ancient lineage that has come to be uniquely and

    evolutionary distinct. Endemic to New Zealand, its numbers have steadily declined since

    the arrival of the first human inhabitants into the country. In the mid 1990s, a new

    conservation approach, comprised of Operation Nest Egg and crching, was initiated by

    the Department of Conservation in an attempt to reverse the population decline, by

    artificially incubating kiwi eggs and releasing the chicks into controlled predator-free

    environments where they can be monitored. Three of these key sites, at varying levels of

    predator presence, were reviewed: (1) Cape Kidnappers and Ocean Beach Wildlife

    Preserve, (2) Boundary Stream Mainland Island, and (3) Opouahi Pan Pac Kiwi Crche;

    that focuses on recovery of the North Island brown kiwi (A. mantelli). However,

    assessments showed that the kiwi populations at these sites are at risk of inbreeding

    depressions and are potentially of mixed genetic makeup. Moreover, population

    viability is jeopardised due to natural dispersal and movement inhibitions, calling for

    continued monitoring and human intervention that involves increasing costs. A review

    of current local approaches and potential to learn from international initiatives should

    be undertaken to guarantee the long-term prospects of kiwi conservation.


    North Island brown kiwi, taxonomy, conservation, Cape Kidnappers, Boundary Stream,

    Opouahi crche, population viability, genetic management.

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    CONTENTS _____________________________________________________________________________________________________


    1.1 Objectives 5

    1.2 Background 5

    1.2.1 Kiwi Taxonomy 6

    1.2.2 Kiwi Biology and Ecology 8

    1.2.3 Plights of the Kiwi 9

    1.3 History of Kiwi Conservation 11

    1.4 BNZ Operation Nest Egg and Kiwi Crche 12


    2.1 Methods Employed 14

    2.2 Advantages 15

    2.3 Disadvantages 15

    2.4 Limitations 15


    3.1 Cape Kidnappers and Ocean Beach Wildlife Preserve 16

    3.1.1 Layout and Initial Setup 16

    3.1.2 Return of the Kiwi 17

    3.1.3 Funding and Costs 18

    3.2 Boundary Stream Mainland Island 18

    3.2.1 Past and Current Management 18

    3.2.2 Predator Control 19

    3.2.3 Reintroductions of the Kiwi 20

    3.3 Opouahi Pan Pac Kiwi Crche 20

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    4.1 Population Dynamics and Viability 23

    4.1.1 Predation Risks 23

    4.1.2 Reserve Size and Habitat Fragmentation 24

    4.2 Phylogenetic Variation and Management 26

    4.3 Cost Effectiveness 29

    4.4 International vs. Local Conservation Approaches 30





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    1.1 Objectives

    This report has been prepared in an effort to contribute to the overall conservation

    practices currently in place for New Zealands iconic national bird, specifically the North

    Island Brown Kiwi (Apteryx mantelli), by aiming to:

    Establish an insight into the issues and concerns affecting kiwi management,

    including their biology, behaviour and conservation history.

    Define and analyse the current procedures of the Bank of New Zealand (BNZ)

    Operation Nest Egg (ONE) and kiwi crche, sanctioned by the Department of

    Conservation (DOC).

    Identify the current North Island brown kiwi population dynamics within three

    key sites in the Hawkes Bay region of New Zealand.

    Provide an assessment on the success of these key sites in kiwi conservation and

    breeding through an analysis of the population viability, genetic management

    and cost effectiveness.

    Examine current local initiatives for kiwi in comparison to international efforts

    involving other endangered species.

    Explore recommendations and improvements to future kiwi conservation


    1.2 Background

    Endemic to New Zealand, the kiwi is known to have evolved around 65 million years

    ago (Holzapfel, et al., 2008). Before the arrival of humans in the 13th century, kiwi

    populations were more widespread (DOC, 2004) and could have been as high as 12

    million birds. Today, the total kiwi population is estimated to be only circa 80,000 birds.

    All taxa are at risk, with some more so than others (BirdLife International, 2008). Also,

    given their rarity, very few New Zealanders have ever seen one in the wild (Peat, 2006).

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    1.2.1 Kiwi Taxonomy

    Initially, there were only three species of kiwi; the brown, the great spotted and little

    spotted. Over the past two decades, the introduction and use of genetic and biological

    data in the early 1990s was a major breakthrough in kiwi species classification,

    especially in the revision of brown kiwi phylogeny. Genetic analysis has resulted in the

    current identification of five formally recognised species, with 4 geographically and

    genetically distinct races distinguished within two of these species (Sales, 2005)

    (Holzapfel, et al., 2008).

    Class: Aves

    Order: Apterygiformes

    Family: Apterygidae

    Species: North Island Brown Kiwi Apteryx mantelli

    Okarito Brown Kiwi/Rowi Apteryx rowi

    Southern Tokoeka Apteryx australis

    Great Spotted Kiwi Apteryx haastii

    Little Spotted Kiwi Apteryx owenii

    The North Island brown kiwi is further split into the following races: the Northland;

    Coromandel; Eastern; and Western populations. Additionally, four races of the Southern

    tokoeka are also recognised: the Haast; Stewart Island; Northern Fiordland; and

    Southern Fiordland populations (DOC, 2004). However, ongoing genetic analysis

    continues to confirm these classifications. As such, the uniqueness in the Haast

    population of the Southern tokoeka is still awaiting formal description, and may be

    elevated to species distinction (BirdLife International, 2008).

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    Figure 1. Map showing the current distribution of the various kiwi species in New

    Zealand. Also featured are 5 kiwi sanctuaries set up on mainland New Zealand during

    2000. Each sanctuary focuses on a specific kiwi taxon: Whangarei on the Northland

    North Island brown kiwi, Moehau on the Coromandel North Island brown kiwi,

    Tongariro Forest on the Western North Island brown kiwi, South Okarito Forest on the

    Okarito rowi, and Haast Range on the Haast tokoeka (BNZ Save the Kiwi Trust, 2011).

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    1.2.2 Kiwi Biology and Ecology

    The kiwi has tiny vestigial wings and no external tail (Holzapfel, et al., 2008). The birds

    have a slow metabolic rate and low body temperature, which are both adaptations to

    enhance energy conservation, and most likely motivated flightlessness. Dimorphism

    also occurs with females generally being larger than males (Sales, 2005).

    The kiwi has a highly developed sense of smell. Their bills are highly efficient at probing

    for food and have specialised pressure sensing nerve endings, which help in detecting

    vibrations of invertebrate in the soil (Sales, 2005). There is also evidence that kiwi

    sometimes feed in rivers and streams, often indulging in freshwater crustaceans like

    koura, highlighting kiwis ability to swim (Peat, 2006).

    Largely nocturnal, the birds leave their burrows at dusk to forage for food (Holzapfel, et

    al., 2008). However, there is evidence of Stewart Island kiwi foraging in the day, due to

    several factors. For example, females incubate their eggs at night, low concentrations of

    food, and/or short summer nights on the island, resulting in only five hours of darkness

    during mid-summer (Peat, 2006).

    Kiwi pair bonds are usually long term. Highly territorial, the paired birds employ

    olfactory signals to mark territories and use far-carrying shrill and guttural calls to

    communicate with each other when out foraging (McLennan, 1988) (Sales, 2005). When

    not foraging, kiwi shelter and nest in burrows, hollow logs or under dense vegetation

    (Holzapfel, et al., 2008). These burrows can be found all over a kiwis territory, with

    some species having several entry points and others just having one (Peat, 2006).

    Egg laying and incubation behaviour varies among the different species (Colbourne,

    2002) (DOC, 2004). Kiwi eggs are one of the largest eggs relative to body weight of all

    birds (Bassett, McLennan, & Blackwell, 2005). Female kiwi usually laid two egg clutches,

    due to having two functioning ovaries, but the rarest species often lay only one egg

    (Peat, 2006). In some species, the male undertakes the entire incubation process, a

    period of up to two and a half months (S