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Post-translocation movements and ranging behaviour of roroa (great spotted kiwi, Apteryx maxima)

Notornis, 69 (3), 135-146

Jahn, P., Ross, J.G., Mander, V., Molles, L.E. (2022)

Article Type: Paper

Translocations are increasingly used in kiwi (Apteryx spp.) conservation management, and their outcome is largely influenced by post-release dispersal and survival. A translocation of roroa (great spotted kiwi, A. maxima) to the Nina Valley, near Lake Summer Forest Park, is the first reintroduction of the Arthur’s Pass roroa population. In 2015, eight wild-caught adults were translocated from Arthur’s Pass National Park, following the release of ten captive-hatched subadults during 2011–13. We monitored the translocated kiwi by radio telemetry during 2015–17. Dispersal was highly variable among the released wild birds. The straight-line distance from the release site to the last recorded location ranged 0.5–10.3 km. Seven of the wild birds remained in the Nina Valley and covered an area up to 1,700 ha (95% utilisation distribution). Releasing the wild birds had no measurable impact on the ranging behaviour of previously released subadults. The current population founder group comprises a maximum of 13 unrelated individuals, and therefore further releases are necessary for a genetically viable population. Additionally, expansion of the pest-controlled area is crucial for the long-term persistence of the reintroduced population in the Nina Valley.

Continued increase in red-billed gulls (Larus novaehollandiae scopulinus) at Otago, southern New Zealand: implications for their conservation status and the importance of citizen science

Notornis, 69 (2), 81-88

Lalas, C., Carson, S., Perriman, L. (2022)

Article Type: Paper

A published national survey of red-billed gulls (Larus novaehollandiae scopulinus) in 2015 recorded about 28,000 nests in New Zealand, a 30% decrease in 50 years. We compared nest numbers in 2020 at Otago, south-eastern South Island, with published records for 1992–2011 and 2015. In contrast to trends further north, numbers at Otago have increased but the average annual rate of increase dropped from 6–10% for 1992–2011 to 2% for 2011–2020. Citizen science provided a valuable input in 2020 with records of breeding at previously undocumented urban locations. The about 6,000 nests at Otago in 2020 probably account for 20% of the national total.

Habitat loss drives population decline and reduced mass of Rakiura tokoeka (Apteryx australis australis, Stewart Island brown kiwi,) at Mason Bay, Stewart Island/Rakiura

Notornis, 69 (3), 147-157

Robertson, H.A., Colbourne, R.M. (2022)

Article Type: Paper

Between 1993 and 2018, the number of Rakiura tokoeka (Apteryx australis australis, Stewart Island brown kiwi) territories in 125 ha of retired farmland near Island Hill Homestead, Mason Bay, declined from 17 to 12 at a mean rate of 1.43% per year, and the minimum number of adults declined by 1.39% per year. These rates triggered a New Zealand conservation status of ‘Nationally Endangered’ for the subspecies assuming that they were typical of the whole of Stewart Island/Rakiura. Feeding habitat for tokoeka has been lost as the study site reverts from rough pasture to flax (Phormium tenax) and scrub; the mean mass of adult birds has decreased by 7.5% over 30 years despite a 30% decline in population density. Key predators of adult kiwi are absent, and predation of Rakiura tokoeka by feral cats (Felis catus) is known but is likely to be insignificant. With a conservative population estimate of 15,000–20,000 adults, and with the decline likely localised at Mason Bay, the conservation status of Rakiura tokoeka is more appropriately classified as ‘At Risk – Naturally Uncommon’. This research highlights the risks of extrapolating results from a single study, in this case with a limited geographical extent rather than a limited duration.

Hosts of the long-tailed cuckoo (Eudynamys taitensis) and museum specimens of the cuckoo’s egg

Notornis, 69 (2), 89-98

Gill, B.J. (2022)

Article Type: Paper

The description of the long-tailed cuckoo’s (Eudynamys taitensis) egg was uncertain until the 1930s. Edgar Stead published evidence in 1936 that it was white with darker (red-brown or purplish) speckles, and therefore mimetic in colour and pattern (as well as size) to the eggs of many small song-birds in New Zealand. In reviewing eggs in museum collections, I find that only one (Auckland Museum LB8968) is certainly long-tailed cuckoo, and only eight other eggs are “probable” (with another eight “possible”). Average dimensions of the nine most likely eggs are 24.1 x 17.4 mm. Field observations of long-tailed cuckoo nestlings, or dependent fledglings receiving food, mostly involve whiteheads, yellowheads, and brown creepers (all in the genus Mohoua, Mohouidae), the principal biological hosts. There are single credible reports of a long-tailed cuckoo nestling being raised in a nest of South Island robin (Petroica; 1880s), silvereye (Zosterops; 1946, plus a vague record from the 1980s), and fantail (Rhipidura; 1963). The scarcity of evidence for non-mohouid hosts, despite the great increase in ornithological field-work since 1963, suggests that use of secondary hosts is extremely rare. Seven other New Zealand song-birds have been cited as hosts of the long-tailed cuckoo, but all reports lack evidence of a cuckoo nestling being raised by the species concerned.

Distribution of great spotted kiwi (Apteryx maxima), 2012-2021

Notornis, 69 (1), 1-18

Toy, R., Toy, S., MacKenzie, D., Simister, K., Yong, S. (2022)

Article Type: Paper

Conservation management requires knowledge of the distribution of species and how this changes over time. Great spotted kiwi (roroa, Apteryx maxima) is classified as globally threatened, ‘Vulnerable’ by the IUCN. It occurs only in the northwest of the South Island of New Zealand, is nocturnal and occurs at low density in mainly remote, mountainous terrain. To determine its distribution, we deployed acoustic recorders at 1,215 locations across 1,400,000 ha between 2012 and 2021. We analysed 3,356 nights of recordings to determine presence and call rates at each location. Roroa were distributed across 848,000 ha, but we identified a core area in northwest Nelson representing just 12% of the distribution (101,000 ha). Within the core, call rates exceeded 3 calls/h at many locations. Call rates provide only a relative indication of abundance but, outside the core, call rates fewer than 0.3 calls/h are common, suggesting that roroa are relatively sparse over much of their distribution. We used a static occupancy model with climatic, topographic and land-cover class variables to better understand the distribution. Eighty percent of recorder-nights had a detection probability exceeding 50%. At this probability, 73% of 5 x 5 km cells surveyed were sampled sufficiently to exceed 90% probability of detection if roroa were present. Annual rainfall and land-cover class appear most important for modelling occupancy. However, comparison of probability of occupancy and actual distribution suggests that variables not included in the modelling, which might include predation, also affect the distribution.

A basic statistical approach to determining adult sex ratios of moa (Aves: Dinornithiformes) from sample series, with potential regional and depositional biases

Notornis, 69 (3), 158-173

Holdaway R.N., Allentoft, M.E. (2022)

Article Type: Paper

Adult sex ratio is a basic component of breeding systems. Estimates of sex ratios of moa (Aves: Dinornithiformes) have ranged from near balanced to significantly female-biased. However, ratios have usually been estimated by simple ratios of females to males identified by some level of sexual size dimorphism or, at most, tested against a balanced ratio by χ2 test. Application of binomial tests confirmed a great heterogeneity, and high levels of uncertainty in estimates of moa sex ratios from different areas and from different kinds of fossil deposits. Large samples gave more constrained estimates than small, but even for some of the larger, binomial analysis often revealed a range of possible ratios, including one with a bias to males. Some causes of extreme values for swamp and lake bed deposits, including sexual differences in territorial behaviour, have been suggested before. However, a new issue – significant and sometimes abrupt changes in female and perhaps male body size through time – was identified here from series of genetically identified and radiocarbon dated moa from North Canterbury, New Zealand. The size changes compromise allocation of individuals to sex by morphometrics of limb bones, especially in undated samples. Intensive radiocarbon dating of series of genetically sexed moa of different taxa from a range of areas will be required to identify potential regional and temporal differences in their sex ratios before any interpretation of the evolution of size dimorphism and breeding systems based on moa sex ratios will be possible.

The detection, breeding behaviour, and use of mangroves (Avicennia marina australasica) by banded rails (Gallirallus philippensis assimilis)

Notornis, 69 (2), 99-111

Beauchamp, A.J. (2022)

Article Type: Paper

This study assessed how tall mangroves were used by a pair of banded rails (Gallirallus philippensis assimilis) with dependent young during three breeding seasons and the intervening periods. Banded rails were territorial and resident all year, raised their young under the mangrove canopy predominantly in dense pneumatophores, and sub-canopy seedlings and saplings. Foraging rails did not follow the tide as it covered and uncovered the flats. Young less than 20 days old were left in cover and delivered food. Young then followed parents as they strolled throughout the site, swam, flew short distances, and climbed mangroves. Rails bathed in and drank saline water and ate worms and crabs. The dependence period of broods was 45–49 days, and in one season, a young bird stayed within the natal site until it was 59 days old.

Measuring conservation status in New Zealand birds: re-evaluating banded dotterel and black-fronted tern as case studies

Notornis, 68 (2), 147-160

J.L. Craig; N.D. Mitchell (2021)

Article Type: Paper

The New Zealand Threat Classification System is used to prioritise and evaluate conservation programs, as an advocacy tool for biodiversity and as a guide to risk when assessing the severity of effects of development. A lack of transparency and adherence to scientific conventions when compiling the listings for birds led to previous criticism (Williams 2009). Two recent papers provide sufficient information to independently assess the threat status ranking of two endemic birds. Both papers provide detailed information on multiple sites and assess the influence of different threats. Both also provide an estimate of population size and generation time as required for assigning a Threat Classification. The authors conclude with clear recommendations on appropriate New Zealand and IUCN threat status ranking in both papers. We consider that the authors have failed to consistently apply the criteria for assessment in the Threat Classification Manual (Townsend et al. 2008) and IUCN Red List Guidelines (IUCN 2019). We re-evaluate the recommended threat status in light of adherence to the criteria, the data used and the analysis methodology selected. We recommend greater transparency, use of additional methodology and adherence to the guidelines to improve consistency and reliability of threat status classification.

Field sexing techniques for Fiordland crested penguins (tawaki; Eudyptes pachyrhynchus)

Notornis, 68 (3), 188-193

J. White; T. Mattern; U. Ellenberg; P. Garcia-Borboroglu; D.M. Houston; P.J. Seddon; H.L. Mays (2021)

Article Type: Paper

Fiordland crested penguins (tawaki; Eudyptes pachyrhynchus) lack sexually dimorphic plumage so behavioural cues or bill size have traditionally been used to determine sex in the field. We aimed to identify morphological characters that can be quickly and reliably be measured in the field to accurately sex adult tawaki, and validated these with genetics. We measured five morphological parameters in tawaki (n = 32) from three colonies (Jackson Head, Milford Sound/ Piopiotahi, and Codfish Island/Whenua Hou) on the New Zealand South Island. We confirmed sex with a PCR-based molecular assay. Male tawaki are larger in all parameters measured and recursive partitioning trees correctly classify 94% of penguins sampled. In line with Warham (1974) and Murie et al. (1991), we propose using bill length (males > 44.5 mm) and bill depth (males > 25.5 mm) but in combination with foot length (males > 113.5 mm) to determine tawaki sex in the field. These morphological parameters are independent of body condition and are easily obtained in the field.

The food and foraging of Collocalia and Aerodramus swiftlets: a review

Notornis, 68 (1), 26-36

M.K. Tarburton; C.T. Collins (2021)

Article Type: Paper

Swiftlets (Collocalia, Aerodramus) make up a guild of birds which prey on a wide range of aerial insects and spiders. The studies reviewed here show their prey to include 19 orders and 55 families of insects plus spiders. Most swiftlets seem to take whatever is available at the time and place, with site to site and year to year differences noted. One species (black-nest swiftlet) appears to be a swarm-feeding specialist. Prey size ranged from

Breeding ecology of a translocated population of great spotted kiwi (Apteryx haastii)

Notornis, 68 (2), 131-146

R. Toy; S. Toy (2021)

Article Type: Paper

Breeding success, survival, and lack of dispersal are all fundamental to the long-term success of animal translocations. Monitoring breeding of great spotted kiwi (roroa, Apteryx haastii) is challenging because they have a low reproductive rate and may abandon eggs or chicks if disturbed. Roroa were translocated to the Flora Stream area, Kahurangi National Park, New Zealand, by the community group, Friends of Flora Inc. and the Department of Conservation. We monitored 55 post-translocation breeding attempts, among 14 roroa pairs, over eight years. Mustelid predation was the only identified cause of chick death. Chick survival to one year is estimated as 26–52%. This is sufficient for population growth, but all chicks known to have survived were hatched by only two pairs. A strategy to monitor long-term genetic health is proposed.
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