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Holocene bird bones found at the subantarctic Auckland Islands

Notornis, 67 (1), 269-294

A.J.D. Tennyson (2020)

Article Type: Paper

More than 3,500 Holocene bones, representing at least 853 individual birds, have been recovered on the uninhabited subantarctic Auckland Islands, south of New Zealand. Today this island group has a rich seabird and land-bird fauna, although there have been at least four bird extinctions (a duck, two petrels and a plover) due to predation by introduced mammals and hunting by humans. The Holocene bone fauna, overwhelmingly from sand dunes on Enderby Island, is dominated by seabirds still found at the island group (particularly diving petrels Pelecanoides spp., southern royal albatrosses Diomedea epomophora, and prions Pachyptila spp.). Remains of all endemic taxa (apart from the Auckland Island tomtit Petroica macrocephala marrineri) were recovered from the deposits. All the taxa known to have gone extinct at the island group have now been recovered in Holocene bone deposits, except for the shore plover (Thinornis novaeseelandiae). The deposits indicate also that the abundance of other species has changed. For example, both the eastern rockhopper penguin (Eudyptes filholi) and white-chinned petrel (Procellaria aequinoctialis) are common in the Enderby Island deposits but are rare on the island today, and the Auckland Island rail (Lewinia muelleri) is present as bones in these dunes but has no historical records from the island. This information on the prehistoric distributions of birds will assist the management of the avifauna of the Auckland Islands, which is currently the subject of a major ecological restoration programme.

Introduced land mammals and their impacts on the birds of the subantarctic Auckland Islands

Notornis, 67 (1), 247-268

J.C. Russell; S.R. Horn; C.M. Miskelly; R.L. Sagar; R.H. Taylor (2020)

Article Type: Paper

Since the European discovery of the Auckland Islands, at least ten species of land mammals have been introduced there. Most arrived in the first half of the ninteenth century during periods of exploitation by sealers and whalers, followed by short-lived Māori and European settlements at Port Ross. Several species required multiple introductions before becoming established. For those populations that naturalised, cattle (Bos taurus) occupied Enderby Island and were eradicated by 1993, goats (Capra aegagrus hircus) remained restricted to the northern end of Auckland Island and were eradicated by 1991, while pigs (Sus scrofa) spread across the entire Auckland Island and remain there today. Rabbits (Oryctolagus cuniculus) established on Rose and Enderby Islands, and were eradicated in 1993. Cats (Felis catus) and mice (Mus musculus domesticus) were both first recorded in 1840 on Auckland Island and remain there today. Rats (Rattus spp.) have never established on the Auckland Islands. Collectively, cattle, goats, sheep (Ovis aries), pigs, and rabbits transformed habitats and altered ecosystem processes, and suppressed tussock, megaherbs, and woody vegetation on Auckland, Enderby, Rose, Ewing, and Ocean Islands. Cats and pigs are together responsible for the extirpation or major reduction of surface-nesting and burrowing seabird colonies, and ground-nesting land birds from Auckland Island. Before dying out on Enderby Island, pigs had similar impacts there. Mice have altered invertebrate community composition and are likely responsible for lower abundancies of wētā (Dendroplectron aucklandense) and large weevils (Curculionidae) on Auckland Island. Disappointment Island remained free of introduced mammals, while on Adams Island they had only fleeting and minimal impact. Humans also had direct impacts on birds through hunting for consumption, with large surface-nesting seabirds severely affected around Port Ross. The Auckland Island merganser (Mergus australis) was driven to extinction by presumed mammal predation and well-documented museum collecting. Eradication of pigs, cats, and mice from Auckland Island and Masked Island (Carnley Harbour) would remove the last introduced mammals from the New Zealand subantarctic region.

Genetic analyses reveal an unexpected refugial population of subantarctic snipe (Coenocorypha aucklandica)

Notornis, 67 (1), 403-418

L.D. Shepherd; M. Bulgarella; O. Haddrath; C.M. Miskelly (2020)

Article Type: Paper

Auckland Island snipe (Coenocorypha aucklandica aucklandica) are presumed to have occurred throughout the Auckland Island archipelago but became restricted to a subset of the islands following mammal introductions. Snipe were known to have survived on Adams Island, Ewing Island, and Disappointment Island. However, it is uncertain whether snipe were continually present on Enderby Island and/or adjacent Rose Island. These islands lie near Ewing Island, and both hosted a suite of introduced mammals until the last species were eradicated in 1993. Using SNPs generated by ddRAD-Seq we identified four genetically distinct groups of snipe that correspond to the expected three refugia, plus a fourth comprised of Enderby Island and Rose Island. Each genetic group also exhibited private microsatellite alleles. We suggest that snipe survived in situ on Rose and/or Enderby Island in the presence of mammals, and discuss the conservation implications of our findings.

Shipwrecks and mollymawks: an account of Disappointment Island birds

Notornis, 67 (1), 213-245

K.J. Walker; G.P. Elliott; K. Rexer-Huber; G.C. Parker; P.M. Sagar; P.J. McClelland (2020)

Article Type: Paper

This paper describes the birds of Disappointment Island, a small pristine island in the subantarctic Auckland Islands archipelago, from an accumulation of observations made by ornithologists during 16 visits to the island during 1907–2019. The island supports large populations of both the Auckland Island rail (Lewinia muelleri) and the Auckland Island teal (Anas aucklandica), most of the global population of the New Zealand endemic white-capped mollymawk (Thalassarche cauta steadi) – an annual average of 63,856 breeding pairs during 2009–17, an estimated 155,500 pairs of the circumpolar white-chinned petrel (Procellaria aequinoctialis), and unquantified numbers of smaller petrels. The topography and vegetation communities of the island are described, the history of visits by ornithologists to the island is outlined, and a list of bird species and their breeding status is recorded.

Reflections on Thinornis rossii

Notornis, 67 (4), 773-781

G.M. Kirwan; N.J. Collar (2020)

Article Type: Paper

Thinornis rossii is a charadriiform taxon represented by a single specimen reportedly collected on the Auckland Islands, south of New Zealand, in 1840, and obviously closely related to the shore plover (T. novaeseelandiae), of mainland New Zealand and the Chatham Islands. Since the early 20th century, the name T. rossii has commonly been treated as a synonym of T. novaeseelandiae owing to doubts over its provenance based on an untraced quotation from the naturalist (Robert McCormick) who was presumed to have collected it. However, there seems to be no other evidence that the specimen might originate from somewhere close to modern-day Auckland, in the northern part of New Zealand’s North Island, rather than the Auckland Islands, despite the fact that the relevant collecting expedition visited both areas. Moreover, the untraced quotation questioning the Auckland Islands origin seems very possibly to be an artefact of a misremembered reading of McCormick’s unpublished diary or his memoirs, and the circumstantial published and unpublished evidence points with reasonable strength to the bird having been collected where originally stated. Morphological characters (darker, browner upperparts, brownish-grey flanks, longer central toe) suggest that T. rossii might be a valid (but extinct) taxon most appropriately ranked at subspecific level, but the possibility remains that it represents a melanistic specimen. Ideally, the type should be subject to a counterpart molecular investigation.

Landscape-scale applications of 1080 pesticide benefit North Island brown kiwi (Apteryx mantelli) and New Zealand fantail (Rhipidura fuliginosa) in Tongariro Forest, New Zealand

Notornis, 66 (1), 1-15

H.A. Robertson; J. Guillotel; T. Lawson; N. Sutton (2019)

Article Type: Paper

Data on the effects of aerial 1080 operations on non-target bird species in New Zealand are scarce and largely limited to short-term colour-banding or radio-tracking studies, or standardised call counts. During a 22-year study in Tongariro Forest, all 142 radio-tagged North Island brown kiwi (Apteryx mantelli) survived 4 landscape-scale (20,000 ha) aerial broadcast 1080 operations targeting brush-tailed possum (Trichosurus vulpecula) and rats (Rattus spp.). Furthermore, both kiwi chick survival to 6 months old and New Zealand fantail (Rhipidura fuliginosa) nesting success were significantly higher in the first 2 breeding seasons following the use of 1080 poison than in subsequent years of the 5-year cycle. We observed several episodes of ferret (Mustela furo) killing multiple adult kiwi, particularly in the last half of the 1080 cycle. Population modelling showed that a 5-year 1080 operation cycle resulted in population gains for 2 years, followed by declines in the remaining 3 years that largely negated these benefits. Our data thus support the shift to a 3-year 1080 operation cycle which will more likely result in this kiwi population growing at close to the 2% per year target set by the 2018–2028 Kiwi Recovery Plan.