The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds

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The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
The State of
New Zealand’s Birds
       2006
      Special Report
  New Zealand’s Seabirds
The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
The State of
    New Zealand’s Birds 2006
                          Special Report Seabirds

    Compiled and edited by Kerry-Jayne Wilson
    The State of New Zealand’s Seabirds 2006 report presents an overview of
    the current status of this country’s seabirds. It seeks to identify those species
    that are in decline and not subject to active management and those for which
    we have insufficient knowledge to know their true status. This statement
    has been written on behalf of the Ornithological Society of New Zealand
    (OSNZ) by ornithologists who share a concern for the well being of our
    birds and their habitats. We hope this publication will highlight the plight of
    our seabirds and encourage the Department of Conservation, OSNZ, other
    NGOs, universities and authorities to focus on research and management that
    address the problems we identify.

    Introduction                                     migration or on foraging forays. A major         species which are, or may be, in decline, but
                                                     threat to New Zealand’s seabirds is fisheries    are not yet sufficiently rare to have become
    New Zealand is a major centre for seabird        bycatch, much of which occurs in waters          a DoC priority.
    diversity. Globally, only about 350 species      outside our jurisdiction, in some cases as far       Some of the seabird survey priorities
    of birds obtain all or most of their food        away as Alaska or Argentina. While mention       identified in this report could be carried
    at sea and at least 84 of these breed in the     is made of threats beyond our EEZ, the           out by the Ornithological Society of
    New Zealand Region. About 38 species             emphasis here is on local issues that we in      New Zealand (OSNZ) or other non-
    of seabird are endemic to New Zealand,           New Zealand can directly address.                government organisations. The best
    meaning they breed here and nowhere                  When it comes to bird conservation the       available information on black-billed gulls
    else. New Zealand now has about as               focus of the Department of Conservation          (Larus bulleri), white-fronted terns (Sterna
    many species of threatened or endangered         (DoC), the government department                 striata), black-fronted terns (S. albostriata)
    seabirds as we have threatened non-marine        charged with the conservation of New             and Caspian terns (S. caspica) was obtained
    birds, yet seabirds receive far less attention   Zealand’s biota, is, and is likely to remain,    during OSNZ surveys in the 1980s or 1990s.
    than their terrestrial counterparts.             on critically endangered species. In recent      The Society should once again take a more
        This report presents an overview of          years DoC and other organisations have           active role in the survey of these and other
    the current status of each group of New          focused on non-marine species at the             accessible species. OSNZ in particular,
    Zealand seabirds. It seeks to identify           expense of seabirds. For most endangered         but other organisations also, have among
    species that are in decline and the main         species that are under direct management,        their membership a host of volunteers who
    threats faced by those species. In this          declines have been halted or in some             would enjoy the opportunity to assist with
    report we deal only with species that breed      cases reversed. However, there are a large       research and management of seabirds. The
    in New Zealand or on the Kermadec,               number of seabird species that are still         Mana Island translocations and Chatham
    Chatham, Snares, Auckland, Campbell,             relatively common but whose populations          Island taiko (Pterodroma magentae) recovery
    Antipodes and Bounty Islands. Many New           are in decline, and other species whose          show what can be achieved at modest
    Zealand breeding seabirds, including most        status is unknown. We hope this report will      cost when this pool of willing and able
    of the endemic species disperse beyond           identify those seabirds for which further        volunteers is tapped.
    our Exclusive Economic Zone (EEZ) during         conservation action is required and those

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The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
We trust that the State of New Zealand’s           Front, reduced food stocks and an
  Seabirds report will provide OSNZ, NGOs,               increase in the frequency of storm
  regional councils and universities with                events.
  direction so that they can supplement the          •   The ozone hole may adversely affect
  good work undertaken by DOC.                           oceanic foraging species as increased
                                                         UV levels may result in a reduction in
                   by Kerry-Jayne Wilson                 primary productivity thus reducing
       Bio-Protection & Ecology Division,Lincoln         the food available to seabirds.
                         University, Canterbury.     •   As a result of predation by introduced
                            wilsok@lincoln.ac.nz         mammals many New Zealand
                                                         seabirds survive only on predator
                                                         free islands. These populations are
  The Key Findings                                       at risk from invasion of their island         Above: Yellow-eyed penguin (Megadyptes antipodes)
                                                         sanctuaries by introduced predators.          Photo by Dave Houston
  • The number of seabirds that are under            •   The eradication of introduced
    threat is increasing.                                mammals, in particular rats, from               of threatened species.
  • Reliable estimates of population size                islands is a vital conservation strategy.     • Much of the research and management
    have been made for very few of New               •   It is now possible to translocate petrel        on seabirds is reactive; there is no
    Zealand’s seabird species.                           chicks from their natal island to another       strategic plan for addressing the needs
  • Research is required on the breeding                 site. This presents exciting new options        of seabirds. A seabird strategy currently
    biology, population dynamics, foods and              for re-establishing petrels on islands          being prepared will hopefully rectify
    foraging ecology for most New Zealand                recently cleared of predators or to             this situation.
    seabird species.                                     predator-fenced areas on the mainland.        • New Zealand currently has a shortage of
  • Fisheries bycatch is a serious threat to         •   With the loss of virtually all of the once      researchers and conservation managers
    most New Zealand breeding albatrosses                huge mainland petrel colonies, over             with seabird expertise. The Department
    and some petrels. Mitigation measures                crowding on small islands and stacks            of Conservation no longer has a scientist
    are being developed for some species.                is apparent and burrow competition              or technical officer employed solely
  • Migratory albatrosses, shearwaters                   may be contributing to declines in              to work on seabirds and field staff
    and other petrels are killed in fisheries            some species. There has been almost             seldom have adequate technical or
    bycatch and perhaps through other                    no research to document the extent to           financial support for the work they are
    marine-based threats in waters far from              which this impacts on burrow-breeding           undertaking. The universities and other
    New Zealand. Even very common                        species.                                        research organisations are similarly
    migratory species such as the sooty              •   Greater public awareness is required of         under resourced when it comes to
    shearwater are in decline.                           the threat that dogs, off-road vehicles         work on seabirds. A heavy reliance on
  • Recreational set-net fishing poses an                and certain recreational activities pose to     contract workers and students means
    unquantified threat to some penguins,                ground nesting seabirds.                        there is little continuity and loss of
    shearwaters and shags.                           •   The shags are the most neglected                skilled workers as people move on at the
  • Changes in oceanic conditions, perhaps               group of seabirds, little is known of the       end of their term. Funding and student
    linked to global warming have the                    population dynamics, breeding biology,          interest has directed seabird specialists
    potential, and may already have                      foods, foraging ecology or population           to work on other taxa.
    contributed to declines in albatross and             status for any of the endemic forms.          • There is opportunity to make more use
    petrel numbers by shifts in the Antarctic        •   The taxonomy of the Leucocarbo shags,           of OSNZ volunteers. Here is a resource
                                                         albatrosses and mollymawks needs to             of keen people looking for opportunities
Top Left: Pancake Rocks, Dolomite Point, Punakaiki       be clarified. Likewise the taxonomic            to contribute to the knowledge and
Photo by Richard Holdaway                                status of the Codfish population of the         conservation of birds.
                                                         South Georgian diving petrel and the          • Seabirds need greater advocacy. Most
Left: Black-winged petrel (Pterodroma                    New Zealand storm petrel need to be             people have little knowledge of them.
nigripennis)                                             determined.                                     Even penguins and albatrosses, the most
Photo by Richard Holdaway                            •   Much of the research conducted by               iconic groups, need greater support.
                                                         DoC on seabirds is driven by pressure           Petrels and terns are ‘out of sight, out
Below: Taiko (Pterodroma magentae)                       from external agencies or issues such as        of mind’ and shags and gulls lack the
Photo by Graeme Taylor                                   fisheries bycatch, rather than the needs        charisma that attracts public support
                                                                                                         for their conservation. There is a need
                                                                                                         to increase the opportunities the public
                                                                                                         have for seeing, experiencing and
                                                                                                         learning about seabirds.

                                                                                                       Birds to Watch
                                                                                                       The species in greatest need of further
                                                                                                       management include, in approximate
                                                                                                       order of priority, the South Georgian
                                                                                                       diving petrel, New Zealand fairy tern,
                                                                                                       Chatham Island taiko, Chatham shag,
                                                                                                       Chatham petrel, Kermadec storm petrel,
                                                                                                       black-billed gull, Pitt Island shag, Chatham
                                                                                                       mollymawk, Westland petrel, Fiordland
                                                                                                       crested penguin, Kermadec petrel, lesser
                                                                                                       fulmar prion, yellow-eyed penguin, black-
                                                                                                       fronted tern, grey-headed mollymawk,
                                                                                                       Bounty Island shag, , erect-crested penguin,
                                                                                                       black petrel and rockhopper penguin.
                                                                                                       The New Zealand storm petrel is a special
                                                                                                       case, when and if its status as a distinct
                                                                                                       endemic species is confirmed it must then
                                                                                                       become a species of particular concern for
                                                                                                       conservation management.
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The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
Albatrosses                                     capped mollymawks. The Department
                                                    of Conservation is currently planning
    New Zealand can be justifiably called the       to eradicate these pigs but face
    home of the albatross, with 13 out of 24        considerable logistic issues. Mouse (Mus
    taxa of the great albatrosses (Diomedea),       musculus) predation has been implicated
    mollymawks (Thalassarche) and sooty             in the decline of Tristan albatross on
    albatrosses (Phoebetria) breeding here. Nine    Gough Island, but there is no evidence
    of these taxa are endemic. The taxonomy         of a similar threat to the Antipodean
    of the albatrosses is currently not settled.    albatross.
    For most of the 20th century it was accepted        A small number of southern royal
    that there were 13 species and a number         albatross on Campbell Island banded
    of sub-species. More recently it has been       in the 1970s suffered injuries from
    suggested each of the 24 taxa probably          poorly fitting or poorly closed bands.
    constitutes a distinct species.                 Department of Conservation staff have             Above: Buller’s mollymawk (Thalassarche bulleri)
        Almost all New Zealand’s albatrosses        spent considerable resources in the last                            Photo by Kerry-Jayne Wilson
    breed on sub-Antarctic islands or the           few years removing these bands. Band
    Chatham group, but there is a small colony      redesign and tighter banding regulation             Below: New Zealand white-capped mollymawk
    of just 20 pairs of Pacific mollymawk on        and supervision will prevent this                                       (Thalassarche cauta) and
    the Three Kings Islands, north of the North     situation occurring in the future.                              Salvin’s (Th. salvini) mollymawks
    Island. Most sub-Antarctic islands support          Currently, all species are recorded as                        Photo by Kerry-Jayne Wilson
    several species of albatross, with Campbell     incidental by-catch in various fisheries.
    Island having six. The only mainland            Direct evidence of bycatch causing
    breeding colony is at Taiaroa Head on           reductions in populations is lacking.
    Otago Peninsula where the first northern        However, there is strong circumstantial
    royal albatross was seen in 1914, the first     evidence that bycatch resulted in
    egg was laid in 1920, but disturbance from      declines in the population of Campbell
    predators and people meant that not until       mollymawks during the 1980s and recent
    1938 did a chick fledge. This success was       suggestions that it may be affecting the
    thanks to ornithologist Lance Richdale’s        population of white-capped mollymawk
    dedicated protection. In 2005-06 there were     on the Auckland Islands. The effect of
    17 nests and more than 65 birds. Predator       fisheries is exacerbated by albatross’s
    control and visitor facilities now give the     propensity to cover vast distances over
    birds and the public a good experience.         large areas of ocean in search of food.
    This is one of most accessible albatross        When breeding, they are more restricted
    colonies in the world for people to visit.      in their choice of feeding area as they
        Albatrosses were hunted by Māori            have to return to their nest. Even so,
    and later by sealers and shipwrecked            breeding albatrosses forage considerable
    sailors until given complete protection         distances, which vary depending upon
                                                                                                     the eggs had hatched, while the chick
    while in the New Zealand realm in 1922.         the stage of the breeding cycle. In recent
                                                                                                     was guarded, the adults made daily trips
    The illegal harvest of small numbers of         years research, using satellite telemetry,
                                                                                                     extending about 200 km east of The Snares.
    albatross and mollymawk chicks continues        has illustrated the foraging ranges of
                                                                                                     When the chick was large enough to be left
    on the Chatham Islands.The majority of          some albatross species in New Zealand
                                                                                                     alone at the nest, the parents alternated
    New Zealand breeding sites are free, or         and complex patterns of food choice have
                                                                                                     between short trips (1–2 days, 200 km) east
    have recently become free of introduced         been revealed. For example, four distinct
                                                                                                     of The Snares to long trips (5–6 days, 780
    mammalian predators. Despite this two           foraging patterns were identified for
                                                                                                     km) along the east coast of the South Island.
    issues remain: pigs (Sus scrofa) are of         Buller’s mollymawk on The Snares. During
                                                                                                     Finally, when the chick was within a few
    concern on the main Auckland Island             incubation, the off-duty parent made trips
                                                                                                     weeks of fledging, female parents switched
    where they take chicks and adult New            averaging 12 days, ranging up to 1,500
                                                                                                     to feeding off the West Coast of the South
    Zealand wandering albatross and white-          km over the Tasman Sea or 750 km along
                                                                                                     Island (trips of 4–5 days and 650 km) and
                                                    the east coast of the South Island. After
                                                                                                                      male parents resorted to
    Table 1: New Zealand’s breeding albatrosses                                                                       trips of about 2 days and 300
                                                                                                                      km around Stewart Island.
                                                                       Population
                                                                       (breeding      Status in    In Fisheries
                                                                                                                          After breeding, adults
    Taxon                           Name                               pairs)         NZ           Bycatch            travel  even longer distances.
                                                                                                                      For example, Buller’s,
    Diomedea antipodensis           Antipodean albatross               8600           Increasing   Yes
    antipodensis                                                                                                      Salvin’s and Chatham
                                                                                                                      mollymawks cross the
    Diomedea antipodensis gibsoni   Gibson’s albatross                 5,800          Stable       Yes
                                                                                                                      Pacific Ocean to forage off
    Diomedea epomophora             Southern royal albatross           8,200-8,600    Stable       Yes                the coast of Chile and Peru.
    Diomedea sanfordi               Northern royal albatross           6,500-7,000    Declining/   Yes                Southern and northern
                                                                                      Stable                          royal albatrosses travel
    Thalassarche chlororhynchos     Eastern yellow-nosed mollymawk     1              Stable       Yes                even further, to feed off
    carteri                                                                                                           the coast of Argentina in
    Thalassarche chrysostoma        Grey-headed mollymawk              6,000-9,000 Declining       Rarely             the South Atlantic Ocean.
                                                                       (p.a)                                          Northern royal albatrosses
    Thalassarche melanophris        Black-browed mollymawk             140             Increasing  Yes                have been tracked using
    Thalassarche impavida           Campbell mollymawk                 19,000-         Stable/     Yes                satellite transmitters. After
                                                                       26,000          increasing                     breeding, they disperse
    Thalassarche bulleri bulleri    Buller’s mollymawk                 13625           Increasing  Yes                east from Taiaroa Head
    Thalassarche bulleri n. ssp.    Pacific mollymawk                  16,000          Unknown     Yes                and the Chatham Islands to
                                                                                                                      locations off Chile, and then
    Thalassarche cauta steadi       New Zealand white-capped           70,000-         Unknown     Yes
                                    mollymawk                          80,000                                         around Cape Horn to feed
                                                                                                                      off Argentina and Uruguay,
    Thalassarche eremita            Chatham mollymawk                  5500            Stable      Yes
                                                                                                                      where they remain until
    Thalassarche salvini            Salvin’s mollymawk                 32,000          Stable      Yes                near the start of the next
    Phoebetria palpebrata           Light-mantled sooty-albatross      7,000 (p.a)     Declining   Rarely             breeding season. To return
                                                                             Sources: Primarily Taylor 2000a, 2000b

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The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
Annual variation in counts of breeding pairs of Buller's mollymawks on                              The number of breeding Antipodean and Gibson’s wandering albatrosses
the North Promontory, The Snares, 1992-2005                                                         alive each year on Antipodes and Adams Island, respectively (estimated by
                                                                                                    mark-recapture analysis of birds banded in the two study areas on Antipo-
                     2000
                                                                                                    des and Adams Islands and fitted regression lines of the log of the number
                     1800                                                                           of birds against time)

                     1600

                     1400
No. Breeding Pairs

                     1200

                     1000

                      800
                                                                          Series1
                      600
                                                                          Linear (Series1)
                      400

                      200

                        0
                            1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
                                                            Year

to their breeding grounds in New Zealand,                                 food supply. The
the birds migrate rapidly eastwards below                                 removal of sheep on
South Africa and Australia, traveling with                                Campbell Island has
the prevailing winds and circumnavigating                                 significantly reduced
the Southern Hemisphere. These                                            the area of suitable
long-distance movements make these                                        breeding habitat but
populations extremely susceptible to                                      has not yet impacted
unregulated fisheries on the high seas or                                 on the burgeoning
traditional inshore fisheries. Less is known                              population of
about the movements of young birds in the                                 Southern royal
years before they breed.                                                  albatross. An
    Grey-headed mollymawks and Light-                                     increase in marine
mantled sooty-albatrosses are rarely                                      mammal numbers
encountered in bycatch. A decline in the
numbers of both species breeding on
                                                                          has been implicated
                                                                          in the loss of breeding habitat, predation          Petrels
Campbell Island recorded since the 1940s                                  and competition for food but this has not
appears to be related to movements in the                                 been quantified. Plastic ingestion has been         New Zealand has the richest diversity of
Antarctic Front causing variation in the                                  implicated in a decline in fecundity in             petrels in the world. Thirty-four species
                                                                            North Pacific albatrosses. Despite the            breed from Kermadec Islands in the north
                                                                            presence of some regurgitated plastic             (29o) to Campbell Island in the south (52o).
                                                                            in New Zealand albatross colonies here            The breeding species include two fulmarine
                                                                            is currently no evidence of any adverse           petrels (Macronectes and Daption), four
                                                                            effects. Disease (which may be a result           large Procellaria petrels, seven shearwaters
                                                                            of global warming or transmission                 (Puffinus spp.), four prions (Pachyptila
                                                                            from researchers) has been implicated             spp.), 11 gadfly petrels (Pterodroma spp.),
                                                                            in the decline of eastern yellow-nosed            four storm petrels (Garrodia, Pelagodroma
                                                                            mollymawk in the Indian Ocean;                    and two Fregetta), and two diving petrels
                                                                            however, there is no evidence that                (Pelecanoides). Ten of these species are
                                                                            disease outbreaks have occurred in New            endemic to New Zealand. The 34 species
                                                                            Zealand albatross populations. There              are further divided into 40 breeding
                                                                            are no reports of large scale oil spills          subspecies. Of these subspecies, 17 are
                                                                            affecting albatrosses in New Zealand.             endemic. The taxonomic status and affinity
                                                                                                                              of two petrels is still uncertain. Black and
                                                                              by Paul Scofield and Paul Sagar                 white storm petrels seen off northern New
                                                                                                             Paul Scofield,   Zealand in recent years may be the New
                                                                                       Canterbury Museum, Christchurch,       Zealand storm petrel (Pealeornis maoriana),
Above: Black-browed mollymawk (Thalassarche
                                                                                        pscofield@canterburymuseum.com        last observed over a century ago. The
melanophris) and Cape Petrel (Daption capense)
                                                                                                                Paul Sagar,   population of South Georgian diving
Photo by Kerry-Jayne Wilson
                                                                                                National Institute of Water   petrels (Pelecanoides georgicus) breeding on
                                                                                                 & Atmospheric Research,      Codfish Island (off Stewart Island) may
Below: Antipodean wandering albatross (Diomedea
                                                                                             P.O. Box 8602, Christchurch,     be an endemic taxon. In addition to the
antipodensis)
                                                                                                       p.sagar@niwa.co.nz     breeding species, a further eight petrel
Photo by Kerry-Jayne Wilson
                                                                                                                              species regularly visit New Zealand seas
                                                                                                                              and another 15 species have been reported
                                                                                                                              as vagrants or beach-cast birds.
                                                                                                                                  All New Zealand petrel species are
                                                                                                                              fully protected under the Wildlife Act
                                                                                                                              1953. However many species are at risk
                                                                                                                              of extinction. The most significant threat
                                                                                                                              is predation by introduced mammals.
                                                                                                                              Formerly the mainland had a host of
                                                                                                                              breeding species that nested from the
                                                                                                                              coastal slopes to the mountain tops.
                                                                                                                              Today only two petrel species nest only
                                                                                                                              on the New Zealand mainland with

                                                                                                                                                                                 5
The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
no island refuges. Westland petrels                scavenge behind fishing vessels. The
    (Procellaria westlandica) nest in rain forest      Procellaria petrels, flesh-footed shearwater
    near Punakaiki and Hutton’s shearwaters            (Puffinus carneipes) and sooty shearwater
    (Puffinus huttoni) in two sites high up on the     (Puffinus griseus) are the species most
    Seaward Kaikoura Range. Tiny remnant               often caught on long-lines or snared
    populations of four other species nest on          during trawl fishing operations. While
    steep coastal cliffs around the main islands       commercial fishing is the main threat,
    of New Zealand. On the Chatham Islands,            recreational line fishing is responsible
    several petrels nest on steep coastal cliffs,      for the deaths of many flesh-footed
    but one species, the critically endangered         shearwaters in northern waters. Set-net
    Chatham Island taiko (Pterodroma magentae)         fishing also impacts on petrels, especially
    nests only in forested valleys on the main         those species that forage close inshore.
    island. All remaining petrel species now           Hutton’s shearwaters, for example,
    breed only on small offshore islands.              have been reported in set-nets on a                  Above: Northern giant petrel (Macronectes halli)
         The densest petrel populations are            number of occasions. Migratory species                               Photo by Kerry-Jayne Wilson
    found on islands free of introduced                are exposed to fisheries impacts both
    predators. Norway rats (Rattus norvegicus),        during the breeding season and during                Below: Westland petrel (Procellaria westlandica)
    feral cats (Felis catus), stoats (Mustela          their non-breeding migratory journeys.                               Photo by Kerry-Jayne Wilson
    erminea) and feral pigs (Sus scrofa) are           For example flesh-footed and sooty
    the most significant predators. Ship rats          shearwaters are taken in salmon gill net
    (R. rattus), kiore (R. exulans), ferrets (M.       fisheries from Alaska south to Oregon.
    furo) and possums (Trichosurus vulpecula)              Other threats include ingestion of
    all impact on petrels at some sites. Weka          plastics and water borne chemicals, and
    (Gallirallus australis) severely impact several    oil spills. These threats are a particular
    of the smaller petrel species and this has         problem for these species that migrate
    lead to population declines on offshore            to distant oceans. For example sooty
    islands to which weka were introduced.             shearwaters have been killed in oil
    Introduced browsing mammals damage                 spills off North America and stomach
    the petrel’s breeding habitat and trample          contents of this species reveal plastic
    burrows.                                           residues probably taken during their
         Introduced predators and browsers             annual sojourn in the North Pacific.
    have been eradicated from a number of              The crowding of petrels onto the few
    offshore islands, the largest being Campbell       remaining predator free islands is yet
    Island (11,300 ha). These eradications have        another problem. On densely burrowed
    removed some of the most significant               islands, suitable nesting habitat is
    threats to breeding seabirds and allowed           scarce and intra- and inter- specific
                                                                                                          population increase (currently about 1000-
    populations to begin recovery. For example,        competition for nest sites can be intense.
                                                                                                          1100 birds).
    Pycroft’s petrel (Pterodroma pycrofti) is          On Rangatira Island in the Chatham Island
                                                                                                               Habitat loss has primarily resulted from
    now increasing in numbers and range on             group, the rare, endemic Chatham petrel
                                                                                                          the loss of the mainland nesting sites due
    the Mercury and Chickens Island groups             (Pterodroma axillaris) competes for burrows
                                                                                                          to predation by introduced mammals. On
    following removal of kiore in the early            with the locally abundant broad-billed
                                                                                                          some islands, the removal of introduced
    1990’s. The eradication of rats on Little          prion (Pachyptila vittata). An intensive
                                                                                                          browsing mammals has created some new
    Barrier and Codfish Islands has allowed            management programme involving
                                                                                                          problems for petrels. Regeneration of native
    Cook’s petrels (P. cookii) on those islands to     finding nesting burrows, converting them
                                                                                                          plants has created dense monocultures of
    breed with greater success and this species        to artificial wooden nest boxes and use
                                                                                                          sedges, vines and ferns on some islands. On
    is likely to soon be down-listed from its          of entrance flaps to prevent prions from
                                                                                                          Macauley Island in the Kermadec group,
    threatened ranking.                                entering has stabilised the small population
                                                                                                          tall Hypolepis fern is smothering breeding
         Fisheries interactions are another major      of Chatham petrels. Breeding success has
                                                                                                          areas and may be displacing the near
    threat to petrels, especially the larger           been raised from 10-30% in the early 1990s
                                                                                                          endemic white-naped petrel (Pterodroma
    species. The species most at risk are those        to around 80%. This has lead to increased
                                                                                                          cervicalis) from its last stronghold.
    that are capable divers and regularly              recruitment of young birds and a modest
                                                                                                          Management of the vegetation may be
                                                                                                                         required until taller forest
    Table 2: Petrel species of conservation concern in New Zealand
                                                                                                                         has re-established. On other
    Conserva-                                                                                    Population trend        islands, introduced weeds
    tion status    Scientific name              Common name               Population size (NZ)   (past 10 years)         have taken over after removal
    Nationally     Pterodroma magentae          Chatham Island taiko      120-150 birds          Slight increase         of browsing mammals. For
    critical       Pelagodroma marina           Kermadec storm petrel     100+ prs?              Stable?                 example, on Motunau Island
                   albiclunis                                                                                            in North Canterbury, boxthorn
                   Pelecanoides georgicus       Codfish Island South      150 birds              Increasing then         (Lycium ferocissimum) (a thorny
                   (Codfish Island)             Georgian diving petrel                           declining
                                                                                                                         shrub capable of snaring
    Nationally     Pterodroma axillaris         Chatham petrel            1100 birds             Slight increase         petrels) became established
    endangered     Pterodroma neglecta          Kermadec petrel           5-10,000 prs           Stable?                 and requires active control. To
                   Puffinus huttoni             Hutton’s shearwater       150-200,000 prs        Slight decrease?
                                                                                                                         our knowledge no outbreaks
    Gradual        Pachyptila desolata          Antarctic prion           Tens of thousands prs? Declining?              of serious viral illnesses have
    decline        Procellaria cinerea          Grey petrel               50-60,000 prs          Declining?
                                                                                                                         occurred in petrels in New
                   Pterodroma cookii            Cook’s petrel             50,000+ prs            Declining?
                   Puffinus griseus             Sooty shearwater          Several million prs    Declining               Zealand.
                   Puffinus carneipes           Flesh-footed shearwater   20,000 prs             Declining?                  In the near future global
    Range          Macronectes halli            Northern giant petrel     2000-3000 prs          Stable
                                                                                                                         climate  change may prove to
    restricted     Pachyptila crassirostris     Chatham Island fulmar     1000-5000 prs          Stable?                 be the major threat to petrels.
                   pyramidalis                  prion                                                                    Sea temperature warming has
                   Pachyptila crassirostris     Lesser fulmar prion       1000 prs               Stable?                 occurred in the past century
                   flemingi                                                                                              and is likely to have caused a
                   Procellaria aequinoctialis   White-chinned petrel      200,000+ prs           Stable?                 decline in ocean productivity.
                   Procellaria parkinsoni       Black petrel              5-10,000 birds         Stable?                 Higher levels of UV light
                   Procellaria westlandica      Westland petrel           2000-5000 prs          Stable?                 exposure in the southern
                   Pterodroma cervicalis        White-naped petrel        50,000+ prs            Increasing?             ocean due to ozone depletion
                   Puffinus bulleri             Buller’s shearwater       Several million birds   Stable?

6
The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
are predicted        Seabird catch in observed sectors of the fishery (estimated total)            Bycatch of Albatrosses
to impact on
chlorophyll
                      3500
                                                                             Japan-NZ tuna
                                                                                                   and Petrels in New
A production
and decrease
                                                                             Hoki traw l           Zealand Fisheries
                      3000                                                   Ling Autoline
productivity                                                                                       Albatrosses and petrels are attracted to
at the base                                                                  Squid traw l
                                                                                                   fishing vessels to feed on discarded fish
of the food                                                                  Total 4 fisheries
                      2500                                                                         and offal. This leads to incidental seabird
chain. Global                                                                                      captures particularly in trawl and longline
climate change                                                                                     fisheries and globally bycatch is recognised
may interrupt         2000                                                                         as one of the main threats to seabird
migration                                                                                          populations. Around 40 species of seabird
patterns for                                                                                       are known to have been caught in New
seabirds, reduce      1500                                                                         Zealand fisheries during the last 10 years.
food stocks and                                                                                    The predominant species caught in New
increase the                                                                                       Zealand fisheries are white-chinned petrel
frequency of          1000                                                                         (Procellaria aequinoctialis), grey petrel (P.
storm events.                                                                                      cinerea), sooty shearwater (Puffinus griseus),
Already severe                                                                                     white-capped mollymawk (Thalassarche
storms have            500
                                                                                                   steadi), Salvin’s mollymawk (T. salvini),
affected some                                                                                      Campbell mollymawk (T. impavida) and
small islands.                                                                                     Buller’s mollymawk (T. bulleri). The New
For example, on           0
                                                                                                   Zealand breeding populations of these
Codfish Island,               1999-00 2000-01 2001-02 2002-03 2003-04 2004-05                      species number in the tens to hundreds of
a storm in 2003                                                                                    thousands. Rarer species such as Chatham
swept out a large                                                                                  mollymawk (T. eremita), Westland petrel
                                                 Chatham Island taiko, Chatham petrel,
section of sand dunes along the beach at                                                           (Procellaria westlandica) and black petrel (P.
                                                 the Codfish Island population of South
Sealers Bay and destroyed 41% of the South                                                         parkinsoni) are caught in small numbers
                                                 Georgian diving petrels and Kermadec
Georgian diving petrel nest sites. The same                                                        sporadically. Little is known about seabird
                                                 storm petrel are the species at greatest risk.
storm also caused the deaths of at least                                                           capture in coastal setnet fisheries which
                                                 Two significant events in 2006 were the
15% of this tiny population of less than 150                                                       probably affect penguins, shearwaters and
                                                 confirmation by Mike Imber and Karen
birds.                                                                                             shags. The extent to which these captures
                                                 Baird that Kermadec storm petrels breed
    Since 1990 the development of petrel                                                           affect the population viability of New
                                                 on the summit of Haszard Island (a tiny
translocation techniques has provided the                                                          Zealand breeding seabirds is unknown,
                                                 stack off Macauley Island), and the first
opportunity for threatened species to be                                                           but research programmes are in place to
                                                 successful breeding by Chatham petrels
transferred to new safe sites and for islands                                                      address this question over the next five
                                                 on Pitt Island in more than a century. The
cleared of pests to have seabirds returned to                                                      years.
                                                 identity of “New Zealand storm petrels”
begin the process of ecosystem restoration.                                                            Monitoring of fisheries bycatch has
                                                 and whether or not they breed in northern
While the status of some threatened petrel                                                         been limited, with coverage of only a
                                                 New Zealand still needs confirmation.
species has begun to improve, there are still                                                      small portion of the fisheries potentially
                                                     Of the 40 subspecies of petrels breeding
several species that will require intensive                                                        interacting with seabirds. There is
                                                 in New Zealand, nearly half are threatened,
management to avoid extinction. The                                                                ongoing monitoring of bird captures in
                                                   declining or have restricted breeding
                                                   ranges (Table 2). The remaining 21              the large-vessel trawl fleets fishing for
                                                   species/subspecies are thought to be            hoki and squid and in selected parts of the
                                                   stable or increasing in numbers following       longline fisheries for tunas and ling. This
                                                   habitat improvements, and not currently         monitoring has shown declines in bycatch
                                                   considered at risk. The location and            rates in the ling autoline fleet following the
                                                   population size of petrel colonies in New       implementation of line-weighting regimes.
                                                   Zealand is poorly known. Only a handful         There has been success in reducing seabird
                                                   of species have had any work done on            take in the Japan-New Zealand tuna
                                                   their population dynamics (survival and         fleet over a period of several years to the
                                                   recruitment rates) and the population           35-50 birds currently caught each year.
                                                   trends for most species has not been            Occasional capture of rare species in these
                                                   studied in a scientifically robust manner.      longline fisheries is a continuing challenge.
                                                   Urgent work is needed on a number               The number of mortalities in 2004/05 in
                                                   of species in view of the potentially           the West-Coast hoki and Auckland Islands
                                                   significant changes expected in the ocean       squid trawl fisheries was around 475 birds.
                                                   environment in the next 50 years (only          This number does not include those birds
                                                   2-3 petrel generations).                        which hit trawl wires and fell into the sea.
Above: Sooty shearwater (Puffinus griseus)                                                             Review of bycatch statistics both with
Photo: Graeme Taylor                                                    by Graeme Taylor,          New Zealand fisheries and internationally
                                                        Research, Development and Improvement      shows that for a particular fishery,
Below: Flesh-footed shearwater (Puffinus carneipes)    Division, Department of Conservation, PO    recognition of the seabird bycatch problem,
Photo: Graeme Taylor                                  Box 10420, Wellington. gtaylor@doc.govt.nz   research and implementation of effective
                                                                                                   mitigation measures often takes around
                                                                                                   five years. This requires coordination and
                                                                                                   cooperation across various government,
                                                                                                   industry and environmental advocacy
                                                                                                   sectors. International initiatives to manage
                                                                                                   seabird bycatch include the International
                                                                                                   Plan of Action on Seabirds promoted by
                                                                                                   the Food and Agriculture Organisation.
                                                                                                   New Zealand is alone in implementing
                                                                                                   a mainly voluntary regime to manage
                                                                                                   bycatch through its National Plan of Action
                                                                                                   on Seabirds.
                                                                                                       Ongoing challenges for reducing
                                                                                                                                                    7
The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
seabird bycatch that affects New Zealand            squid, salmon smolt and Antarctic krill
    breeding species are; the reduction of offal        – but a diet based on tinned sardines
    and whole-fish discharge from vessels,              preserved in soya oil has since been used
    and the capture of New Zealand breeding             successfully for six species, with fledging
    species in foreign fisheries as the birds           rates of up to 100%. Hand-feeding of
    migrate to other areas around the globe, in         chicks is labour intensive, and volunteer
    particular the waters off South America and         involvement in caring for the chicks has
    South Africa.                                       been a feature of most translocations.
                                                            Seven species of petrels have been
                             by Susan Waugh,            recovered as adults at their release sites,
           Fisheries Sciences, Ministry of Fisheries,   with five confirmed breeding. However,
                                         Wellington     for five species; few birds (1-4) have yet
                                                        been recovered at release sites and for at
                                                        least two of these, a higher proportion
    Petrel Translocations                               of translocated chicks have returned to
                                                        the source population. To date, only two
    There are two main reasons to translocate           translocations have resulted in large
    petrels: as part of recovery programmes for         numbers of birds returning to the release         Top: Sweetwater exclosure, Alison Davis, Liz and
    threatened species, and to restore their role       site – 32 fluttering shearwaters on Maud                                             Bruce Tuanui
    as ecological drivers at sites from which           Island, and 20 common diving petrels on                                 Photo by Graeme Taylor
    they have been extirpated. Burrowing                Mana Island. While we now know how
    petrels had profound effects on many                to get large numbers of chicks to fledge in       determine annual survival. Blood samples
    New Zealand terrestrial ecosystems, both            good condition, we still do not know how          have been collected from all birds handled
    on islands and on the mainland. Impacts             to overcome the strong instinct of most           since 1996. These have been used to sex
    included the importation of vast quantities         individuals to return to their natal colony.      the birds and are currently being analysed
    of marine nutrients (especially nitrates                                                              to assess genetic relationships within the
    and phosphates), and the creation of a                                   by Colin Miskelly,           population. All chicks are captured in April
    subterranean network of tunnels providing                Wellington Conservancy, Department of        or early May to be banded and measured.
    living space and habitat for a diversity of              Conservation, P.O. Box 5086, Wellingon.      Small transmitters are attached to ensure
    other animals. Eradication of introduced                                   cmiskelly@doc.govt.nz      that all chicks make it safely to sea. Every
    mammals from islands or fenced mainland                                                               year a few of the fledglings need to be
    sites is often a prerequisite for restoration
    of petrel colonies, but predator eradication        Chatham Island Taiko                              taken out to the coast after crash-landing in
                                                                                                          the forest.
    alone may be insufficient to guarantee                                                                     The species has a precarious hold on
    success. Most petrels are highly faithful to        The Chatham Island taiko (Pterodroma
                                                        magentae) was rediscovered in 1978 by             its existence. Mark-recapture estimates put
    their natal colony, and the establishment of                                                          the population at 120-150 birds. In 2005/06,
    a new colony depends on overcoming this             David Crockett, solving a puzzle that
                                                        linked bird bones on the Chatham Islands          the number of known breeding pairs edged
    strong homing instinct.                                                                               up to 15 and a record 11 chicks fledged.
        The two main techniques used to attract         with a petrel specimen collected at sea in
                                                        the 1860s. It took nearly ten years to locate     Over ten banded chicks have now returned
    petrels to new or ancestral sites are sound                                                           to the scattered colony. The main hope for
    attraction, and translocations of chicks in         the first breeding burrows. In 1987/88, only
                                                        three taiko breeding burrows were known,          the species’ future lies with the Sweetwater
    the last few weeks before fledging. Solar-                                                            Covenant, a predator proof fenced hilltop
    powered sound systems that automatically            at the head of the Tuku River on main
                                                        Chatham Island, 4-5 km inland in tall, wet        about 500m from the coast. The site was
    switch on at dusk and off at dawn                                                                     gifted by landowners Bruce and Liz Tuanui
    broadcast calls of species that visit their         forest.
                                                            Over the last 20 years, a large team          and funding for the fence was secured by
    colonies at night, giving the impression                                                              the Chatham Island Taiko Trust. In October
    of an active breeding colony. These had             of dedicated workers and volunteers
                                                        committed to saving this enigmatic species        2006 a sound attraction unit with taiko
    been installed at ten sites by 2006. Between                                                          calls was installed and the first taiko chick
    1986 and 2006, ten separate attempts were           from extinction have contributed to taiko
                                                        recovery. The work has entailed protection        transfers to this site are planned for 2007.
    made to translocate chicks of eight petrel
    species in New Zealand. However, many               of all known breeding colonies, finding
    of these attempts were too recent to yet            more breeding sites and monitoring all                                  by Graeme Taylor,
                                                        known taiko pairs and their breeding                    Research, Development and Improvement
    determine their success, as most petrel
                                                        activity.                                         Division, Department of Conservation, PO Box
    species do not return to land until 3-5
                                                            Department of Conservation workers                   10420, Wellington. gtaylor@doc.govt.nz
    years old. Several of the earlier attempts at
    translocation were specifically to develop          trap and poison introduced predators and
                                                        browsers and protect taiko nests. The main
    seabird translocation techniques, either
                                                        target species are feral cats (Felis catus) and   Black Petrel
    generic, using fluttering shearwaters
    (Puffinus gavia) and common diving petrels          rats (Rattus sp.). Locating new burrows
                                                        has involved the cooperation of David             The endemic black petrel (Procellaria
    (Pelecanoides urinatrix), or as analogues for                                                         parkinsoni) once bred on coastal and inland
    more threatened species, grey-faced petrel          Crockett and his team of OSNZ volunteers,
                                                        conservation staff and supportive                 ranges of the North and upper South
    (Pterodroma macroptera) for Chatham Island                                                            Islands. They are now only found on Little
    taiko (P magentae), and Pycroft’s petrel (P.        landowners. Every 2-3 years a radio
                                                        telemetry project involves spotlighting           and Great Barrier Islands in the Hauraki
    pycrofti) for Chatham petrel (P. axillaris).                                                          Gulf. The Great Barrier Island population
    Other species translocated to date are black        taiko as they fly inland toward their
                                                        breeding sites, capturing these birds and         is estimated to be 1600 breeding pairs with
    petrel (Procellaria parkinsoni), fairy prion                                                          approximately 100 pairs on Little Barrier
    (Pachyptila turtur), Chatham petrel and             attaching tail-mounted radio transmitters.
                                                        The birds are then tracked to pinpoint            Island.
    Hutton’s shearwater (Puffinus huttoni).                                                                   The Great Barrier population is affected
        All translocations involved hand-               promising search areas. Ground teams
                                                        then head in after dark to locate the birds,      by predation by rats (Rattus sp), feral cats
    feeding all or some chicks, though some                                                               (Felis catus) and occasionally feral pigs
    species become very fat as nestlings and            hopefully at a new burrow site. In recent
                                                        years, a specially trained dog and handler        (Sus scrofa). Little Barrier Island is now
    need little food in their last week or so                                                             predator-free, but once had kiore (Rattus
    before fledging. Translocations of diving           have joined the search and have been
                                                        successful in finding new burrows.                exulans) and feral cats which preyed
    petrels and fairy prions have required daily                                                          heavily on the petrels. Black petrels
    or twice-daily feeding of all chicks. Earlier           Burrow monitoring, mainly in October
                                                        each year, has concentrated on capturing          scavenge behind fishing vessels and have
    translocation attempts used relatively                                                                been recorded in the bycatch of long-line
    natural food such as fresh or frozen                birds at the burrows for banding and to
                                                                                                          fisheries in New Zealand waters. They

8
The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
may also be at threat from bycatch in                                               Paul Scofield,    plied by fisherman and naturalists, birding
foreign waters during their migration                          Canterbury Museum, Christchurch,       trips which use chum (fish waste) to attract
and wintering period in South America.                          pscofield@canterburymuseum.com        seabirds close to the observers’ boats is a
Recent deployment of data loggers has                                                                 recent development. Alternatively, perhaps
shown that during breeding black petrels                                                              their numbers are increasing following
forage more widely than expected; around            Pycroft’s Petrel                                  recent eradication of rodents from nearby
New Zealand visiting Fiordland and the                                                                islands. Whichever, it seems likely that the
Chatham Rise with some also going to                The status of Pycroft’s petrel (Pterodroma        population has persisted unnoticed ever
eastern Australia and Fiji.                         pycrofti) is representative of many New           since those specimens were collected in the
    We have monitored the Great Barrier             Zealand breeding petrels. They once               19th century.
Island population since the 1995. During            bred at Norfolk Island and probably at                Confirmation that the birds seen are
this study, population estimates, breeding          mainland sites in northern New Zealand,           the same species as the three museum
success, mortality factors and survival rates       as well as many offshore islands. With the        specimens has been slow in coming, mainly
have been determined. Over 1500 adult               introduction of mammalian predators the           because this required the capture of birds.
birds and 1200 chicks have been banded.             species became extinct on the mainland            In November 2005 a bird flew into the cabin
Population models suggest that the                  and survived only on a few islands that           of a boat anchored off Little Barrier Island.
population is in slight decline, (estimated         remained free of introduced predators. The        The bird was held overnight and next day
decline 2.8% per year) and that adult               species can persist, at least in the medium       Richard Griffiths and Karen Baird were
survival is lower than for other petrels.           term, with kiore (Rattus exulans). Island         there to band, measure, and photograph
Despite low adult survival, breeding                surveys in the 1970’s and 1980’s located          it. A further three birds were captured
success was high, with chicks fledging              some breeding sites and it is likely that they    in January 2006. All birds were banded,
from three quarters of eggs laid. Survival          also bred on other poorly surveyed islands.       measured, photographed, and fitted with
of pre-breeders is 92%, which indicates             No accurate counts were ever made and             a small radio-transmitter before release.
that juveniles are returning to the colony in       few of these islands have been resurveyed.        Unfortunately, only one bird was detected
good numbers.                                       Other than general accounts of the breeding       at sea and no signals were received from
    The black petrel population appears             cycle virtually nothing else is known             birds on land. These captures support the
to be fairly stable, but is still at risk from      of its biology. The species is threatened         assertion that these birds do indeed belong
land-based threats such as rats and feral           but not at immediate risk of extinction.          to the same species as those museum
cats on Great Barrier Island and at sea from        Pycroft’s petrel numbers have apparently          specimens, and are a distinct species. The
undetermined fisheries-related mortality.           increased following the eradication of            birds’ identity is currently being reviewed
                                                    kiore from some islands where the petrels         by the Ornithological Society of New
by Elizabeth Bell, Joanna Sim and                   survived. Because Pycroft’s petrel is less        Zealand’s Rare Birds Committee.
                     Paul Scofield                  at risk than other small Pterodroma species           Now the main priority is to discover
                                  Elizabeth Bell,   it has been used to develop translocation         their breeding location, to estimate the
  Wildlife Management International Limited,        methodologies for use with it’s rarer             population size and assess population
    35 Selmes Road, Rapaura, RD3, Blenheim,         congeners. Chick development, meal size           trends so that protection can be ensured.
               New Zealand, wmil@clear.net.nz       and feeding frequencies were studied so           Molecular work is also underway to
                                    Joanna Sim,     that translocated Pterodroma chicks could         compare the four captured birds with the
    Department of Conservation, Great Barrier       be fed prior to fledging. Pycroft’s chicks        museum specimens and other storm-petrel
 Area Office, Port Fitzroy, Great Barrier Island,   have been translocated from Red Mercury           species. Fieldwork planned for the 2006/07
                New Zealand, jsim@doc.govt.nz       to Cuvier Island and the species used to          summer involves the further capture of
                                                    develop burrow protection devices for the         birds, attachment of transmitters, and
                                                       protection of the critically endangered        survey of islands where they may breed.
                                                       Chatham petrel (P. axillaris). As with
                                                       most other petrels that are not under
                                                       immediate threat their status and biology
                                                                                                                    by Brent M. Stephenson
                                                                                                        Eco-Vista: Photography & Research + Wrybill
                                                       remains little known.
                                                                                                         Birding Tours, NZ, PO Box 8291, Havelock
                                                                                                                    North 4157. brent@eco-vista.com
                                                                    by Kerry-Jayne Wilson
                                                        Bio-Protection & Ecology Division, Lincoln
                                                          University, Lincoln. wilsok@lincoln.ac.nz   Penguins
                                                                                                      Despite being an iconic group and the
                                                      New Zealand Storm Petrel                        subject of countless documentaries, New
                                                                                                      Zealand penguins remain enigmatic with
                                                      Until 2003, the New Zealand storm-petrel        all too much still unknown. Of the six
                                                      (NZSP) was known from only three                species that breed in the New Zealand
                                                      specimens held in museums in France             region (four of which are endemic), five are
                                                      and England. It was thought to be either        in decline.
Above and Below: Chatham petrel
                                                      a rare colour morph of Wilson’s storm-               Mammalian predators including dogs
(Pterodroma axillaris)
                                                      petrel (Oceanites oceanicus), or a distinct,    (Canis familiaris), cats (Felis catus), ferrets
Photos by Graeme Taylor
                                                      but extinct species, Pealeornis maoriana.       (Mustela furo) and stoats (M. erminea) are
                                                          Then in January 2003 Sav Saville and        the traditional foes of mainland nesting
                                                      Brent Stephenson spotted a small black          penguins and although advances in
                                                      and white storm-petrel, they suggested          trap technology and dog legislation has
                                                      could be a NZSP, off Whitianga. In              seen some small reduction in penguin
                                                      November 2003 a small ‘flock’ of these          mortality, a solution to mainland predator
                                                      birds was seen in the Hauraki Gulf and          problems is unlikely in the foreseeable
                                                      sightings of these birds in northern New        future. Where there is some protection
                                                      Zealand have continued from October to          from predators, blue penguins (Eudyptula
                                                      April each year.                                minor) can do well and there are some
                                                          Where have these birds suddenly             significant populations on islands and
                                                      appeared from and are they indeed               predator controlled sites. Elsewhere, their
                                                      NZSPs? Perhaps their dramatic                   populations are seeing slow declines and
                                                      rediscovery is an artifact of the recent        localised extinctions. A growing problem
                                                      interest in pelagic bird watching.              for the blue penguin, and to a limited
                                                      Although the Hauraki Gulf has been well         extent the yellow-eyed penguin (Megadyptes

                                                                                                                                                        9
The State of New Zealand's Birds 2006 - Special Report New Zealand's Seabirds
eyed penguins is a must for many of               predation by cats (Felis catus). However,
                                                         the tourists that visit coastal Otago, but        despite there being no evidence that chicks
                                                         the pressure of tourist numbers at some           were still lost to cats, few chicks have
                                                         sites and the overcrowding of facilities          fledged in the last three years.
                                                         is seeing spillover into other breeding                Disease has been an issue for both
                                                         sites where, because of their value to the        Stewart Island and Otago Yellow-eyed
                                                         penguin population, viewing has been              populations, with the Corynebacterium
                                                         discouraged and visitor facilities, like          outbreak of 2004 claiming around 50% of
                                                         hides, do not exist.                              all chicks. A blood parasite, formerly only
                                                             While the tourists may get a “natural”        known from Fiordland crested penguins
                                                         experience there is growing evidence              (Eudyptes pachyrhynchus), has also recently
                                                         that the penguins are suffering, with             been identified in yellow-eyed penguins
                                                         increased levels of stress hormones               on Stewart Island. The poor years of the
                                                         and reduced chick fledge weights (and             late 1980’s and bio-toxin induced mass
                                                         thus lower survival) documented. The              mortality event of 1989 can be linked to El
                                                         behaviour of some visitors undoubtedly            Nino/southern oscillation events, but other
                                                         contributes to this, as some visitors             marine factors are having unknown and
                                                         pursue penguins to get a better photo.            perhaps immeasurable impacts.
                                                             Fiordland crested penguins (Eudyptes               Recent research has confirmed that
                                                         pachyrhynchus) are even more susceptible          yellow-eyed penguins forage almost
                                                         to human disturbance and even though              exclusively on the sea floor. Some penguins
                                                         the numbers of tourists are a fraction of         have been drowned in nets set on the sea
                                                         those viewing yellow-eyeds, most of the           bottom even in waters up to100m deep,
                                                         Fiordland penguin colonies accessible to          however information on the frequency
                                                         the public are in decline. The sensitivity        of capture is sparse. Evidence is also
                                                         of these birds to disturbance has even            emerging of yellow-eyed penguins foraging
                                                         seen the monitoring of breeding at some           in areas of sea bed disturbed by trawling
                     Above: Snares crested penguin       South Westland sites suspended.                   and dredging. The impacts, if any, of this
                               (Eudyptes schlegei)           The Snares penguin (E. robustus) is           disturbance to the penguin’s marine habitat
                           Photo by Dave Houston         the one species that is not in decline, the       are unknown.
                                                         last census in 2000 revealing a similar                So if things aren’t too good on
     antipodes), is coastal development. Coastal         number of breeding pairs to previous              the mainland, what’s going on in the
     subdivisions and other developments can           counts. Why they alone should have a                “stronghold” of the species, the Auckland
     result in a decrease the amount of suitable       stable population is puzzling, but the              and Campbell Islands? The truth is we
     nesting habitat, an increase the numbers          proximity of The Snares to the nutrient-rich        don’t really know, the last census of these
     of domestic dogs and raise the risk of road       Southland current may be a factor.                  islands was carried out 15 years ago.
     kills.
         Habitat protection alone is not sufficient                            by Dave Houston                                      by Dave Houston
     to ensure the long-term viability of penguin            Wellington Conservancy, Department of                Wellington Conservancy, Department of
     populations, as the state of the yellow-                Conservation, P.O. Box 5086, Wellingon.             Conservation, P.O. Box 5086, Wellington.
     eyed and crested (Eudyptes sp) penguins                                   dhouston@doc.govt.nz                                 dhouston@doc.govt.nz
     can attest. While the former, at least in
     its mainland habitat is still subject to the
     pressures of introduced predators, most           Yellow-Eyed Penguin                                 Shags
     crested penguins live on remote sub-
     Antarctic islands that are largely predator       Over the last 20 years much effort has been        New Zealand’s shags (cormorants) fall
     free, yet all but one species are in apparent     put into the conservation of the yellow-           into two distinct groups. Those that
     decline.                                          eyed penguin (Megadyptes antipodes) in             predominantly use freshwater or estuarine
         The plight of the rockhopper penguin          Otago, its principal mainland range.               habitats and those that are primarily,
     (Eudyptes chrysocome) is the most dramatic.       Efforts, lead by the Yellow-eyed Penguin           or exclusively marine. The freshwater/
     Its population on Campbell Island has             Trust and Department of Conservation,              estuarine species also occur in Australia
     collapsed from 1.6 million breeding pairs in      have been focussed on the two problems             and some species in other counties as
     the 1940’s to just over 100,000 pairs in 1985     identified in the early 1980’s – predators         well. The New Zealand populations of
     and there is no evidence to indicate that         and breeding habitat. Predator control is          the pied (Phalacrocorax varius varius) and
     the decline has halted. A similar decline         ongoing at many sites, significant areas           little shags (P. melanoleucos brevirostris)
     in rockhoppers has also been noted on the         of coastal land have been protected and            are sub-species endemic to New Zealand.
     Antipodes Islands and in the erect-crested        the slow process of ecological restoration         Within New Zealand, all four species (black
     penguin (E. sclateri) population there and        started, but yellow-eyed penguin numbers           (P. carbo), pied, little and little black (P.
     at the Bounty Islands.                            have not increased significantly.                  sulcirostris) are widespread and moderately
         The reasons for the rockhopper                    On Stewart Island the situation is             common, although the little black shag
     penguin’s decline are unclear but are most        worse. The first
                                                                               Population trends for the yellow-eyed penguin in Otago
     likely related to changes in food availability,   census, completed
                                                       in 2003, revealed a        700
     either from reduced marine productivity
     or shifts in prey distribution. While             population of just
                                                                                  600
     natural marine and climate cycles may be          178 breeding pairs,
     involved, so may human influence through          alarmingly short           500
                                                       of the previous
                                                                               Breeding Pairs

     either global warming or fishing. Our
     knowledge of the foraging ecology of these        estimates of 470-          400
     species is at best basic and without baseline     600 pairs. The lack
     information, detecting and understanding          of young and non-          300
     changes is difficult.                             breeding birds in
         Tourism has the potential to be of            what appears to            200
     benefit to some species, as it has been for       be a population
     blue penguins in Oamaru, who instead              in decline saw             100
     of being considered pests and accused of          research and
                                                       management                    0
     trespass are now a valued asset. Tourism
     is not always so benign. Viewing yellow-          efforts focussed on           1980        1985           1990         1995           2000        2005

10
breeds only in the North Island. The black        population of the Stewart Island shag
shag is one of few native birds that is not       increased in both range and numbers
totally protected. The most comprehensive         during the 1990s but further south trends
population surveys and population and             are confusing. Each with populations
breeding studies are being carried out in         of about 2000 pairs, the Stewart Island
the Wellington region where black shag            and Campbell Island shags are the most
and little shag numbers may have declined.        secure of the New Zealand species in
Recent trends elsewhere are unknown.              this genus. The Chatham shag appears
The biology of black and pied shags is            to have undergone a large decline with
moderately well known but little and little       counts in 2003 suggesting a population
black shags have been little studied.             of only a third of that recorded in 1997.
    The marine shags are all endemic to           The Chatham shag is almost certainly the
New Zealand, all but one have restricted          most threatened of New Zealand’s shag
distributions and most are of conservation        species. Counts also suggest a decline
concern. Three taxa, spotted (Stictocarbo         in the numbers of Bounty Island shags.
punctatus), blue (S. punctatus steadi) and Pitt   However, for both species counts are
Island (S. featherstoni) shags are generally      not strictly comparable and latter counts
placed in the genus Stictocarbo although          could reflect poor breeding seasons in the
shag taxonomy is subject to ongoing debate        second year counts were done. There is
and some taxonomists place all shags in           little census data for any of the remaining
the genus Phalacrocorax. The spotted shag         species but they appear to be small
has a discontinuous distribution from             (80%) of the New Zealand
the genus Leucocarbo. The taxonomic               New Zealand shags is desirable, the need          population breeds between 34 and 38°S.
relationships of these species need               for research is most urgently required            The location of breeding sites seems related
revision but on the basis of their disjunct       for the marine shags. Almost none of              to sea-temperature, which determines the
distributions and variations in morphology        the census, survey or research priorities         availability of food for these primarily fish
each is currently treated as a separate           identified for New Zealand shags in 2000          eating birds. The predominant prey species
species. Recent fossils found in parts of         have been addressed. Recent counts are            of Australasian gannets in New Zealand are
New Zealand not currently occupied by             strongly indicative of declines in Chatham,       inshore pelagic schooling fish and diurnal
Leucocarbo shags gives credence to the            Pitt Island and Bounty Island shags. For          squid. Differences in diet at different
view that the New Zealand king shag               all three species the most optimistic counts      gannetries are evident, and some seasonal
(L. carunculatus) and the Stewart Island          show populations of c600 pairs. Research          variation is also apparent. Gannets also
shag (L. chalconotus) are in fact variants of     to determine the reasons for declines and         take discards from boats, and will feed on
the same species and molecular studies            ways to reverse these declines is urgently        quite large flatfish at the back of trawlers.
being conducted by Martyn Kennedy at              required. The New Zealand king shag is                National population counts date back
the University of Otago, could result in a        the rarest of the New Zealand shags but its       to the 1940s and much has been published
further reduction in the number of species        population is probably stable. Shags remain       on their basic biology. Censuses have been
recognised. The King shag is restricted           a poorly studied group whose conservation         conducted in New Zealand in the 1946/47,
to the outer regions of the Marlborough           needs are inadequately documented. Even           1969/70, and 1980/81 breeding seasons, and
Sounds, and the Stewart Island shag occurs        easily accessible species, such as the spotted    this has suggested an annual population
in Otago, Southland and Stewart Island.           shag, have attracted little attention from        increase of 2.3%, with the population in
The Chatham (L. onslowi), Auckland (L.            researchers. Most shag colonies have not          1980/81 estimated at 46,004 breeding pairs
colensoi), Campbell (L campbelli) and Bounty      been censused for at least a decade and           in NZ, and 6660 in Australia. A national
(L. ranfurlyi) shags are each confined to         therefore the population estimates and            census was conducted in the 2000/01
those respective island groups. The diet,         trends indicated here might be unreliable.        breeding season, but the results of this
foraging ecology, population dynamics and                                                           are yet to be published, although results
breeding biology are not adequately known                         by Kerry-Jayne Wilson             indicate a continued increase, with some
for any New Zealand Leucocarbo species.               Bio-Protection & Ecology Division, Lincoln    gannetries remaining stable. The current
    The king shag is endangered with a                  University, Lincoln. wilsok@lincoln.ac.nz   population estimate is 55,000 breeding pairs
total population of only about 645 birds.                                                           in New Zealand and 20,000 in Australia.
However, counts over the last decade                                                                    With regards to population changes,
suggest the population is stable. The Otago                                                         three gannetries have been well studied,

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