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Short term effects of an aerial 1080 operation on mātātā (South Island fernbird, Poodytes punctatus punctatus) in a South Island wetland

Notornis, 69 (4), 203-210

C. Kilner; J. Kemp; G. Elliott (2022)

Article Type: Paper

Abstract: New Zealand conservation managers use aerial 1080 (sodium fluoroacetate) to control invasive mammalian predators, often with the aim of protecting populations of threatened endemic birds. Matātā (South Island fernbird, Poodytes punctatus punctatus) are endemic to New Zealand wetlands and are vulnerable to mammalian depredation. Mātātā populations might benefit from aerial 1080 predator control, but they also can suffer non-target poisoning losses. This study measured the short-term effects of an aerial 1080 operation on mātātā adult survival (i.e. non target mortality) and nest survival (over one breeding season) on the West Coast of South Island. The study utilised two sites, with an October (mid-breeding-season) aerial 1080 operation at one of the sites. We found no evidence of a negative short-term effect of aerial 1080 – none of fourteen colour-banded adult mātātā exposed to 1080 baits died of 1080 poisoning. Conversely, we found evidence of a short-term positive effect – aerial 1080 improved mātātā nest survival over one breeding season. The presence of a positive effect, in the absence of a negative effect, suggests that the net effect of the 1080 operation for the mātātā population was positive, at the end of the breeding season.


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

Notornis, 69 (2), 99-111

A.J. Beauchamp (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.

When the lonely goose? Implications of a revised history of the lake and its surrounding vegetation for a radiocarbon age for the only South Island goose (Cnemiornis calcitrans) from the Pyramid Valley lake bed deposit, New Zealand

Notornis, 69 (1), 19-36

A.G. Johnston; B.C. Duffy; R.N. Holdaway (2022)

Article Type: Paper

A high resolution chronology of deep water charophyte algal remains in the Pyramid Valley lake deposit, North Canterbury, South Island, New Zealand, records the presence and drainage of a previously unsuspected much larger (c. 50 ha) lake. The larger lake occupied the surrounding basin and the present lake (1 ha) was a semi-isolated embayment at its south-western margin. Fluctuating lake levels and its final drainage drove changes in the vegetation and hence in the habitats available for the avifauna recorded in the rich fossil record. A high precision radiocarbon age on the only South Island goose (Cnemiornis calcitrans) in the fauna coincided with the presence of lowland forest and not with the brief period when sedges and grassland colonised the newly exposed former lake bed. This suggests that the South Island goose was able to survive in different habitats through successive glacial-interglacial vegetation cycles. Information from other disciplines can be essential to interpreting both a fossil site and the circumstances surrounding the presence of a particular species in it.



A New Zealand island in change: 38 years of landbird populations affected by habitat restoration and invasive mammalian predator control

Notornis, 69 (4), 211-228

C.J. Ralph; C.P. Ralph; P. Martins; P.L. Ralph (2022)

Article Type: Paper

Abstract: Bird abundances on a small island (150 ha) near the mainland of northern North Island New Zealand were studied using a standardised, longitudinal survey through 38 years (1988–2020), a period during which habitat restoration, reintroductions of five native bird species, and control of rats (Rattus spp.) and stoats (Mustela ermina) occurred. We estimated time-series abundances of 33 bird species and found substantial population shifts shared by many taxa. The unique data set from this restoration project showed that: (1) more species and more individual birds were present at the end of the study than at the beginning; (2) rat control made an immediate and lasting difference, increasing population growth of the typical species 6% per year; (3) boosting ecological succession by habitat conversion and habitat enrichment resulted in a long term population growth of many native bird species; (4) shifts in species composition are still ongoing 20 years after predator control, with both gradual, long-term increases, and declines. In particular, two endemic species, and pōpokotea (whitehead, Mohoua albicilla) proved robust competitors in a predator- free environment, increasing in abundance, while most non-native and many native species declined. These gradual, longer-term shifts became clear during “maturation”, a period beginning about 13 years after predator control started.



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 <1 to 13 mm in body length and is related to swiftlet body size. Habitat and elevational differences may represent resource partitioning in foraging strategies.


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.

A survey of Fiordland crested penguins (Eudyptes pachyrhynchus): northeast Stewart Island/Rakiura, New Zealand, September 2019

Notornis, 68 (3), 183-187

R. Long; S. Litchwark (2021)

Article Type: Paper

A ground survey of Fiordland crested penguins (tawaki; Eudyptes pachyrhynchus), breeding between Lee Bay and White Rock Point, northeast Stewart Island was carried out from 1–6 September 2019, to obtain a population estimate for the area. A total of 128 nests was found along the ~40 km of coast, 107 of which were located in caves on the cliffy shoreline rather than in the forest as is typical of South Westland breeding areas. Access along this coast is often difficult; however, the confinement of most nests to caves allows for a more accurate search than in forest colonies such as those in South Westland and Milford Sound. The results of this survey suggest that a significant breeding population is present on mainland Stewart Island and needs to be considered in future management plans for the species. Additional surveys of the remaining ~700 km of coastline should be conducted to obtain a better estimate of the entire population.

Clutch sizes and hatching success of Canada geese nesting in Canterbury, New Zealand

Notornis, 68 (1), 13-25

J.S. Adams; M. Williams (2021)

Article Type: Paper

Nesting outcomes of Canada geese (Branta canadensis maxima) in Canterbury, New Zealand were recorded from a sedentary population nesting at coastal Lake Forsyth (1967–70) and from a seasonally migratory population nesting in headwater valleys of the Waimakariri River (1966–80). Mean clutch size in 462 Lake Forsyth nests was 5.3 (sd = 1.3) eggs, with clutches of 4, 5, and 6 eggs comprising 17%, 30% and 30% respectively of the total. Goslings hatched from 67.4% of 1,602 eggs in 298 monitored nests, and the entire clutch hatched successfully in 42.6% of the monitored nests. Mean productivity at hatching was 3.6 (sd = 2.3) goslings per nest. Mean clutch size in 1,211 Waimakariri River headwaters nests was 4.5 (sd = 1.3), with clutches of 4, 5, and 6 eggs comprising 25%, 32%, and 20% respectively of the total. Goslings hatched from 63.3% of 3,952 eggs in 871 monitored nests, and the entire clutch hatched successfully in 30.5% of the monitored nests. Mean productivity at hatching was 2.9 (sd = 1.9) goslings per nest. Relative to Canada geese in their native North American range, geese nesting at Lake Forsyth laid clutches of similar size, had similar hatching success but higher nest success whereas geese nesting in the Waimakariri River headwaters laid, on average, conspicuously smaller clutches, had similar hatching success, but higher nest success.

Estimating the distribution, population status, and trends of New Zealand scaup (Aythya novaeseelandiae)

Notornis, 68 (2), 108-130

B.S. Greene (2021)

Article Type: Paper

New Zealand scaup (Aythya novaeseelandiae) counts are collated from a total of 12,145 site visits nationally between 1888 and 2018 to estimate their distribution, population status, and trends. Based on systematic counts of large flocks on lakes between 1984–2018, there are about 11,000 New Zealand scaup nationally. This estimate must be interpreted with caution, as if birds are highly mobile the risk of overestimating the population is high. The distribution of New Zealand scaup strongholds (>50 adults) is compared to historical descriptions and trends in water quality. As lakes become more eutrophic over time, the birds move and the population declines. Research should focus on aerial vs ground counts, telemetry/satellite and/or banding studies of bird movement, gender, diet, predation, and littoral zone quantity and quality (<10 m deep). To achieve this, it is recommended that a national waterbird management and monitoring plan be developed.

Diet of the Floreana mockingbird (Mimus trifasciatus) during the dry season on Champion and Gardner Islets, Galápagos Islands, Ecuador

Notornis, 68 (4), 245–252

C. Wittmer-Naranjo; E.M.R. Reyes; H.E.T. Jácome; D. Rueda; C.; Sevilla; L. Ortiz-Catedral (2021)

Article Type: Paper

The Floreana mockingbird (Mimus trifasciatus) is one of the most endangered passerines in the world, with a global population of c. 400 individuals, restricted to two isolated islets: Champion and Gardner-by-Floreana. Due to its rarity and the inaccessibility to these islets, the biology of the Floreana mockingbird has remained poorly documented. Here we present a study on the diversity of food items consumed by Floreana mockingbirds prior to the rainy season. We recorded 269 foraging bouts, from 148 individuals on three independent sampling events. Floreana mockingbirds exhibited a generalist diet, which included flowers, nectar, stamens, sap, fruits, seeds, and seedlings from 12 plant species; larvae, pupae and adults of at least 10 arthropod orders; and small vertebrate prey, carrion, and egg contents. The diversity of food items between months and islets supports the idea of a generalist diet for the species. Our study provides useful information to identify and monitor the abundance of key resources for the species as part of the restoration of Floreana Island.

Nocturnal activity of the western weka (Gallirallus australis australis) in an open environment

Notornis, 68 (1), 1-12

S.D. Lamb; H.R. Taylor; R. Powlesland (2021)

Article Type: Paper

Understanding how animal behaviours are affected by external factors such as time of day/year and weather conditions is fundamental to understanding the basic biology of a species and can thus help with conservation management. Weka (Gallirallus australis) is typically crepuscular in its habits, but there is some evidence to suggest that it can also be nocturnal. We conducted a longitudinal study of the nocturnal habits of the western weka (G. australis australis) located at Manaroa in New Zealand’s Marlborough Sounds. We used model selection information criterion to examine how the numbers of weka in an open environment (lawn) changed with time of night and season, as well as differing weather and moonlight conditions. In addition, we undertook night-time behavioural observations during a four-month subset of the study period. Numbers of weka declined through the night and increased non-linearly around dawn. Weka were more likely to be present during moonlit nights and at warmer temperatures during the evening. There was considerable seasonal variation, with the highest number of weka during autumn and lowest during summer. Behavioural observations demonstrated that weka were active throughout the night, with foraging being the most frequently-observed behaviour.

Increasing urban abundance of tūī (Prosthemadera novaeseelandiae) by pest mammal control in surrounding forests

Notornis, 68 (2), 93-107

N. Fitzgerald; J. Innes; C. Watts; D. Thornburrow; S. Bartlam; K. Collins; D. Byers; B. Burns (2021)

Article Type: Paper

Public and our observations during 1999–2004 suggested that tūī (Prosthemadera novaeseelandiae) visited the city of Hamilton during March to October only, outside the nesting season. From 2004 onwards, we captured and banded 51 adult tūī and fitted radio transmitters to 41 in Waikato urban areas to locate nests. We directly observed 15 nests to determine nesting success and gather evidence of any predation events. Tūī moved 5–23 km from urban areas to surrounding native forests at the onset of nesting, but only four (29%) of 14 unmanaged nests fledged young, due mostly to predation by ship rats (Rattus rattus), swamp harriers (Circus approximans), and brushtail possums (Trichosurus vulpecula). Subsequent effective pest mammal control in forests around Hamilton was associated with greatly increased year-round tūī abundance and nesting in Hamilton. These results confirm previous findings that tūī move widely in winter; that they readily cross pasture in the absence of forest corridors, and that they will permanently inhabit urban areas. Provided adequate food is available, effective control of ship rats and possums can rapidly (1–4 years) increase tūī visits and nesting within 20 km of managed sites, enabling recolonisation of proximate urban habitats by this iconic endemic taxon, despite previous evidence for natal philopatry.