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Aberrant and deformed Antarctic penguins and unusual eggs

Notornis, 67 (2), 459-468

S.V. Golubev (2020)

Article Type: Paper

Nineteen cases of physical deformities, colour aberrations, and unusual eggs were recorded in emperor penguins (Aptenodytes forsteri) and Adélie penguins (Pygoscelis adeliae) from the Haswell archipelago in the Davis Sea, East Antarctica, during 1956–2016. Two very small eggs and one very large egg were recorded from emperor penguins, and two very small eggs from Adélie penguins. Physical deformities included beak deformities in two emperor penguin adults and two chicks, and two chicks had deformed spines. Colour aberrations included the ino mutation in a juvenile emperor penguin, and examples of dilution (two cases), progressive greying (two cases), and isabellinism in adult Adélie penguins. Feather-loss disorders were recorded in two downy emperor penguin chicks. Data on the occurrence of identified abnormalities and disorders are given. These cases provide a baseline for assessing changes in the frequency of physical abnormalities in these Antarctic penguin species.

Movements of New Zealand ruddy turnstones (Arenaria interpres)

Notornis, 67 (4), 659-672

D.S. Melville; A.C. Riegen; R. Schuckard; (T.)A.M. Habraken (2020)

Article Type: Paper

Ruddy turnstone (Arenaria interpres) is the third most numerous Arctic-breeding wader that occurs in New Zealand. Numbers of turnstones in New Zealand have declined but identification of potential causal factors is hampered by lack of information of the migration routes used. Re-sights of marked birds indicate that some New Zealand turnstones pass through East Asia and Australia on both northward and southward migration. Information on possible migration through the Pacific is lacking.

First northern giant petrel (Macronectes halli) breeding population survey and estimate for the Auckland Islands, New Zealand

Notornis, 67 (1), 357-368

G.C. Parker; R.K. French; C.G. Muller; G.A. Taylor; K. Rexer-Huber (2020)

Article Type: Paper

This first breeding population estimate of northern giant petrels (Macronectes halli) in the Auckland Islands group involved whole-island censuses, apart from the main Auckland Island, in the 2015-16 breeding season, and multi-year repeat visits to a subset of island colonies. Parallel line-transects in giant petrel habitat were used to survey the number and spatial distribution of pre-fledging chicks. The Auckland Islands 2015-16 whole-island census resulted in a count of 216 northern giant petrel chicks on eight of the 15 islands in the group. Applying a simple correction factor, the breeding population in 2015 is estimated as c. 340 breeding pairs (range 310–390). This estimate is higher than historical non-quantitative records of 50–200 breeding pairs. Multi-year counts on Enderby, Rose, Frenchs, Ocean, Disappointment, and Adams Islands showed some inter-annual variability, but other island colonies remained more stable. The northern giant petrel colony on Enderby Island has increased from two chicks in 1988 to 96–123 chicks in 2015–18 (four annual counts undertaken).

Birds of the Auckland Islands, New Zealand subantarctic

Notornis, 67 (1), 59-151

C.M. Miskelly; G.P. Elliott; G.C. Parker; K. Rexer-Huber; R.B. Russ; R.H. Taylor; A.J.D. Tennyson; K.J. Walker (2020)

Article Type: Paper

The Auckland Islands are the largest island group in the New Zealand subantarctic region, and have the most diverse avifauna, including eight endemic taxa. We present the first comprehensive review of the avifauna of the Auckland Islands, based on a database of 23,028 unique bird records made between 1807 and 2019. At least 45 species breed (or bred) on the islands, with a further 77 species recorded as visiting the group as migrants, vagrants, or failed colonisers. Information on the occurrence of each species on the different islands in the group is presented, along with population estimates, a summary of breeding chronology and other reproductive parameters, and diet where known. The frequency at which 33 bird species were encountered during visits to the seven largest islands is compared graphically to facilitate comparison of each island’s bird fauna in relation to habitat differences and the history of introduced mammals. Disappointment Island (284 ha) is the least modified island in the group. However, it lacks forest, and so has a very restricted land bird fauna, lacking ten species that breed on other islands in the group. Auckland Island (45,889 ha) is the only major island in the group where introduced mammals are still present. As a result, it also has a depauperate bird fauna, with at least 11 species completely absent and a further seven species reported at lower frequencies than on the next largest islands (Adams and Enderby Islands).

Distribution, long term population trends and conservation status of banded dotterels (Charadrius bicinctus bicinctus) on braided rivers in New Zealand

Notornis, 67 (4), 733-753

C.F.J. O'Donnell; J.M. Monks (2020)

Article Type: Paper

Banded dotterels (tūturiwhatu, Charadrius bicinctus bicinctus) are small plovers inhabiting New Zealand’s braided rivers, estuaries, seashores, and open country. They are considered Nationally Vulnerable under national threat listing criteria, but with uncertainty around the trend estimation. We collated and reviewed counts of banded dotterels on their braided river breeding grounds from throughout the country, 1962–2017, to describe their distribution, assess population trends, estimate rates of population change, and assess the appropriateness of the threat status given to this species. We also used nationwide winter count data for banded dotterels from 1984 to 2018 as an independent measure to compare trends. Banded dotterel counts were recorded for 119 braided and shingle river reaches, mostly in the South Island (87%) with far fewer rivers in the North Island (13%). The sum of banded dotterel counts was 12,730 birds when tallying the most recent counts/river. Although they were most widespread in the South Island, particularly Canterbury, the majority (>50%) of dotterels counted on the most recent surveys were from just 10 (8%) rivers with the largest single concentrations on three Hawkes Bay rivers. Counts suitable for long-term trend analysis were only available for South Island sites. Widespread declines in banded dotterel count indices were recorded. The weighted mean annual rate of change across 33 South Island rivers was -3.7% p.a. (per annum), which equates to a 52.3% decline over 20 years (~3 generations). We also detected a negative trend in dotterel numbers based on national winter count data, but of a smaller magnitude (-1.4% p.a., equating to a 25% decline over 20 years). However, trends in Australia, where c. 60% of banded dotterels over-winter, are unknown. In contrast, a significant population increase was measured on the Hakatere Reach of the South Ashburton River, which has intensive, sustained predator control, and several predator trapping initiatives on other braided rivers and coastal areas indicate declines can be reversed with management if applied at an extensive landscape scale. Banded dotterels are subject to a wide range of threats including very high levels of predation by invasive predators, human disturbance on breeding grounds, and habitat loss and degradation. Using the precautionary principle, the rates of decline on South Island braided rivers confirm the classification of Nationally Vulnerable using the NZ Threat Classification system. However, results suggest that the IUCN threat status for banded dotterel should be reclassified from Least Concern to Endangered.

Breeding of little penguins (Eudyptula minor), including multiple brooding, at South Bay, Kaikōura, New Zealand, 2006–2017

Notornis, 67 (2), 451-459

L.K. Rowe; J.S. Weir; A.G. Judkins (2020)

Article Type: Paper

For 11 breeding seasons, a colony of little penguins (Eudyptula minor) was monitored at South Bay, Kaikōura. The 106 breeding attempts from 86 pairings consisted of 68 single clutches, eight attempts made up four replacement clutches (an unsuccessful original clutch followed by a second clutch by a pair in one season), 26 attempts consisting of 13 double broods (a successful original clutch followed by a second clutch by a pair in one season), and one complex triple brood (three successful attempts by a penguin in one season, the triple brood, plus another successful attempt by its first mate after separation). The earliest laying date was 18 April for multiple brooders and 12 August for single clutch pairs. Single clutch pairs raised a mean of 1.42 fledglings/clutch. Four pairs with first clutch failures laid replacement clutches; one was successful. Seven of the 13 pairs of double brooders successfully raised the second clutch; the productivity of the 13 pairs was 2.69 fledglings/pair. The first record of a successful triple brood by little penguins was complex in that the female separated from her mate after the first brood chicks fledged, and then completed her second and third broods with a different male. Her original mate also produced a further brood with another female to complete his double brood. These four clutches laid eight eggs of which seven hatched and six chicks fledged. This may also be the first reported multiple brood with a change of mate after a successful first brood. On a colony-wide basis productivity per season was 2.36 eggs/pair, 1.80 chicks/pair, and 1.66 fledglings/pair. Previous research indicated Kaikōura birds belonged to the New Zealand Only (NZO) clade of little penguins. As double brooding and rafting are traits of the Australia and south east New Zealand (ASENZ) clade only, this classification is now questionable suggesting a mix of both clades and/or hybrids.

Population trends of light-mantled sooty albatross (Phoebetria palpebrata) at Adams Island and trials of ground, boat, and aerial methods for population estimates

Notornis, 67 (1), 341-355

K. Rexer-Huber; K. Walker; G. Elliott; G.B. Baker; I. Debski; K. Jensz; P.M. Sagar; D.R. Thompson; G.C. Parker (2020)

Article Type: Paper

Population sizes of light-mantled sooty albatross (Phoebetria palpebrata, LMSA) at the three New Zealand breeding sites (Auckland, Antipodes, and Campbell Islands) are poorly known. Annual counts since 1999 of a small number of LMSA nests show a long-term population decline on Adams Island, Auckland Islands. Mean nest numbers in 2016-17 were 10% down on counts in 1999–2000, with an annual rate of decrease, lambda, of 0.44 in the period 1999–2019. Three methods to estimate the breeding population size were trialled: ground counts of nests (Adams); aerial photography of LMSA with ground-truthing (Adams); and boat-based counts of LMSA on coastal cliffs (Campbell). Ground counts in a clearly delimited area were repeatable (42 and 40 active nests in 2017 and 2018, respectively), thus useful for monitoring, but ground counts are too limited for a whole-island population estimate. Aerial photography overestimated the number of active nests by 12.5% compared with ground counts. Ground-truthing showed that most apparently occupied nests contained an egg, and so nests occupied by birds with no egg are a smaller error source when interpreting aerial photographs than for other albatrosses. Boat-based LMSA counts proved inaccurate due to vessel movement. Considering that the terrain favoured by LMSA is very difficult to access, population size estimates based on aerial photography with ground calibration for apparent breeders appear the most effective of the techniques trialled. Ongoing counts at vantage-point and ground-count sites enable continued monitoring of LMSA trends at Adams Island.

Breeding petrels of Breaksea and Dusky Sounds, Fiordland; responses to three decades of predator control

Notornis, 67 (3), 543-557

C.M. Miskelly; C.R. Bishop; T.C. Greene; J. Rickett; G.A. Taylor; A.J.D. Tennyson (2020)

Article Type: Paper

Twenty-four breeding colonies of three petrel species were found on 18 of 26 islands surveyed in Breaksea Sound/Te Puaitaha, Fiordland National Park, New Zealand, in November 2017 and December 2019. All vegetated islands within Breaksea Sound were surveyed, along with 20 islands in Dusky Sound/Tamatea that were not included in an initial survey in November 2016 (eight of these additional Dusky Sound islands had breeding petrels, including three with broad-billed prions Pachyptila vittata). Sooty shearwater (Ardenna grisea) was the most widespread and abundant species in Breaksea Sound, with an estimated 6,950 burrows on 14 islands, while broad-billed prions were breeding on seven islands (2,100 burrows estimated). We record the first evidence of mottled petrels (Pterodroma inexpectata) breeding in Breaksea Sound, which is now their northernmost breeding location. Burrow occupancy rates were not assessed for any of the species. Most of the islands in Breaksea Sound had previously been surveyed during 1974 to 1986, before Norway rats (Rattus norvegicus) were eradicated from Hāwea and Breaksea Islands, and stoats (Mustela erminea) controlled to near zero density on Resolution Island and adjacent islands (including the inner Gilbert Islands and Entry Island). Following pest mammal control or eradication, broad-billed prions have colonised at least four additional sites. Sooty shearwaters were found at five sites in Breaksea Sound where they had not been recorded in 1980–83, and at one site they had increased by more than 50-fold since rat eradication. When combined with data from the 2016 and 2017 surveys, more than 75,700 petrel burrows are estimated to be present in southern Fiordland.

Ornithological discovery, exploration, and research on the Auckland Islands, New Zealand subantarctic

Notornis, 67 (1), 11-58

C.M. Miskelly; R.H. Taylor (2020)

Article Type: Paper

The Auckland Islands comprise the largest and most researched island group in the New Zealand subantarctic region, and have the largest number of endemic bird taxa. Paradoxically, they are the only one of the five island groups that has not yet been the subject of a comprehensive avifaunal review. We summarise the history of ornithological exploration of the group, and where this information is held, based on a database of 23,028 bird records made between 1807 and 2019. More than 76% of these observations were unpublished, with the two largest sources of information being Heritage Expedition wildlife logs (5,961 records) and records collected during the Second World War coastwatching ‘Cape Expedition’ (4,889 records). The earliest records of endemic taxa are summarised, along with the earliest records of significant seabird breeding colonies. Citizen science (principally eBird, with 1,597 unique records) is a rapidly growing source of information, and new records of vagrant species continue to accumulate at a rapid rate. Compared with other subantarctic islands, Auckland Islands’ birds have received very little research attention, with most effort to date focused on a few large surface-nesting seabird species.

Towards the reestablishment of community equilibrium of native and non-native landbird species in response to pest control on islands in the Eastern Bay of Islands, New Zealand

Notornis, 67 (2), 437-450

C.J. Ralph; C.P. Ralph; L.L. Long (2020)

Article Type: Paper

Disequilibrium of bird communities, due to introduced pests and human-caused habitat changes, is a fundamental property to be understood in restoration of island biota. In this paper, we suggest that the reestablishment of native forests and food webs favour long-established and native species, and is less favourable to more recently introduced species. To test this hypothesis, we compared population trends of native and non-native birds on five islands in the Ipipiri Group in the north of New Zealand. We used over 900 station counts starting in 2008 when habitat recovery and pest (rat [Rattus], mouse [Mus musculus], and stoat [Mustela erminea]) removal began, as well as comparing to a set of earlier counts. In general, we found that detection rates of most long-established endemic native species significantly increased, while non-native species mostly decreased, suggesting population increases and decreases, respectively. Of the native species, six are relatively recent natural immigrants to New Zealand, and most of these declined or remained unchanged. We suggest that the increase in long-established natives is likely due to increased size and quality of native bush areas making habitat more favourable to these natives, as well as reduced predation and competition from the pest mammals.

Notes on staging bar-tailed godwits (Limosa lapponica baueri) at Ouvéa (Loyalty Islands, New Caledonia) during southward migration in 2007

Notornis, 67 (4), 651-656

R. Schuckard; D.S. Melville (2020)

Article Type: Paper

During southward migration from Alaska in 2006, a satellite-tracked female bar-tailed godwit (Limosa lapponica baueri) encountered adverse weather and stayed between 19 September and about 28 September 2006 at Ouvéa (Loyalty Islands, New Caledonia), where she apparently died. Ouvéa was visited between 27 September and 7 October 2007 to look for godwits. A total of eight godwits was recorded of which one, thought to be an adult female, may have been a dropout migrant. The remaining birds appeared to be immatures.

Variation in the bill colour of the white-capped mollymawk (Thalassarche cauta steadi)

Notornis, 67 (1), 333-340

A.J.D. Tennyson (2020)

Article Type: Paper

The white-capped mollymawk (Thalassarche cauta steadi) and Tasmanian mollymawk (T. cauta cauta) have discreet breeding sites, but away from their breeding grounds, where their at-sea ranges overlap, they are difficult to identify. The bill colour of these taxa has recently been considered to differ, but there is much conflicting information in published accounts. Three key differences often discussed are the amount of yellow on the culminicorn, the amount of yellow on the cutting edge to the upper mandible, and the amount of darkness on the mandibular unguis. In January 2018 I assessed these characters in 100 adult white-capped mollymawks at their Disappointment Island breeding site and found that each character was variably present. The majority of white-capped mollymawks lacked a yellow base to their culminicorn and had a dark mark on their mandibular unguis. In contrast, it has been reported that the majority of adult Tasmanian mollymawks have yellow at the base of their culminicorn and lack a dark mark on their mandibular unguis. While these characters can be used as a guide to identify these taxa, a minority of individuals of each taxon show the ‘typical’ bill colours of the other taxon. The amount of yellow on the cutting edge to the upper mandible varied between individual white-capped mollymawks, and so this is not a useful identification character.

Individual variation in the foraging behaviour of two New Zealand foliage-gleaning birds

Notornis, 67 (3), 526-542

I.G. McLean (2020)

Article Type: Paper

The foraging behaviour of two foliage gleaning birds, rifleman and grey warbler (henceforth warbler), was studied at Kowhai bush, Kaikoura, with the aims of exploring behavioural variation by individual pairs, and broader patterns of foraging behaviour for each species. Data on six foraging variables were collected from individually identifiable birds of known breeding status at the time of sampling. A total of 1,632 samples were taken during the spring/summer period of 1987/8. Data analysis explored foraging behaviour in relation to species, sex, and breeding stage. Individual pairs of riflemen exhibited significant variation in behaviour, indicating behavioural specialisation that I term a “foraging personality” identified as an emergent characteristic of each pair. Riflemen showed greater within-pair variation than warblers. The similarities and differences in foraging behaviour between the two species are described and are linked to their behavioural ecology. Analyses are presented in relation to the problem of data independence when repeated samples are taken from one individual.

Changes in the number and distribution of northern New Zealand dotterels (Charadrius obscurus aquilonius): results of four censuses undertaken between 1989 and 2011

Notornis, 67 (4), 717-728

J.E. Dowding (2020)

Article Type: Paper

This paper presents the results of four censuses of the northern New Zealand dotterel (Charadrius obscurus aquilonius) population undertaken between 1989 and 2011. During that period, the population increased by roughly 50%, from about 1,320 to about 2,130 birds. Most birds (85%) were in the northern part of the North Island (Northland, Auckland, and Coromandel Peninsula), but the taxon is expanding its range southwards on both the west and east coasts. On the east coast, a few pairs are now breeding close to Cook Strait. Population trends varied between regions, and almost all of the overall increase was a result of increases on the east coast. The highest rates of increase were on the Auckland east coast and on Coromandel Peninsula, probably because the intensity of management has been highest in those regions. In the Auckland urban area, birds now routinely breed inland, mainly on grass or bare earth; elsewhere, the taxon is almost entirely coastal. The proportion of birds on the west coast has fallen over the past 50 years, and about 85% of the taxon is now found on the east coast. If the overall increase in numbers has continued at the same rate since 2011, there would be about 2,600 birds in 2020. The size of the population and its rate of increase justify the recent down-listing of the subspecies to a threat ranking of At Risk (Recovering), but it remains Conservation Dependent. The recovery programme has been highly successful, and most management of the taxon is now undertaken by community groups, regional councils, and volunteers. Continuing threats include predation, flooding of nests, and disturbance during breeding; in future, continuing coastal development and increased recreational activity will probably degrade habitat further, particularly on the east coast, and climate change will have a range of impacts.