Publications Archive

  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.  

  We found widespread nesting on the ground in a large population of feral rock pigeons (Columba livia) in an urban, but predator-free native forest reserve in Christchurch, New Zealand. Ninety-seven percent (n = 77) of rock pigeon nests were located on the ground, with most placed either at the bases of large kahikatea (Dacrycarpus dacrydioides) trees or under a tangle of vines on the forest floor. Clutch size was 2 eggs in all nests, with a hatching success of 93.9% in nests that survived to the hatch stage. Overall nest success was higher (60.0%) than in other populations of rock pigeons, with half of nest failures attributed to culling of the population that occurred during the course of our study. On average, rock pigeons fledged 1.60 chicks per successful nest. No ground nests were located outside the boundary of the predator- proof fence, suggesting pigeons were able to assess predation risk when selecting nest site location. Ground nesting by rock pigeons may be a way to avoid damage to nests in the canopy by strong winds or predation from aerial predators such as harrier (Circus approximans), which also occur in the reserve. Based on density of nests, we estimated a breeding population of 226 to 258 rock pigeons in the 7.8 ha reserve. The high number of pigeons in the reserve highlights the need for further studies on how populations of introduced species of birds in New Zealand respond to control of mammalian predators and the effect this may have on sympatric native species.  

  Birds were banded in gardens at Rangiora 1961–1977, Christchurch 1977–2000, and Kaikōura 2000–2016. In total, 21,565 birds of 14 species were captured in mist-nets or traps and banded; 3,213 individuals were recovered or recaptured. The most common species banded was silvereye (Zosterops lateralis lateralis) with 15,349, followed by house sparrow (Passer domesticus domesticus) with 4,497, and common starling (Sturnus vulgaris vulgaris) with 430; all other species were less than 300 birds banded which is less than five birds per year. Distance recoveries of note are: silvereyes – Kaikōura to Wellington (153.0 km), Rangiora to Greymouth (146.0 km), Rangiora to Otira (99.0 km), with two more birds over 25.0 km; house sparrow – Christchurch to Homebush (43.5 km), with two more over 25.0 km; common starling – Rangiora to Christchurch (27.8 km); dunnock (Prunella modularis) – local movement (5.1 km). The most significant recoveries from time of banding to recovery are: silvereye – 8.8 years; house sparrow – 8.7 years; starling – 8.0 years; dunnock – 5.3 years. Wing length and mass measurements of Kaikōura birds were generally within published ranges.  

  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.  

  Thirty breeding colonies of three petrel species were found on 23 of 41 islands and one of three headlands surveyed between Milford Sound/Piopiotahi and Dagg Sound/Te Rā in Fiordland National Park, New Zealand, in November 2020. Sooty shearwater (Ardenna grisea) was the most widespread and abundant species, with an estimated 7,300 burrows on 20 islands and one mainland site. Broad-billed prions (Pachyptila vittata) were found breeding on five islands (600 burrows estimated), including an islet in Poison Bay, 70 km north-east of their previous northernmost Fiordland breeding location. We record the first evidence of mottled petrels (Pterodroma inexpectata) breeding in Doubtful Sound/Patea (on Seymour Island), which is now their northernmost breeding location. When combined with data from surveys in southern Fiordland between 2016 and 2021, more than 66,000 pairs of petrels are estimated to be present in 168 colonies in Fiordland. This total comprises 42,100–52,400 sooty shearwater pairs, 11,700–14,500 broad-billed prion pairs, 5,090–6,300 mottled petrel pairs, and at least 1,000 common diving petrel (Pelecanoides urinatrix) burrows. This is the first near-complete estimate of petrel population sizes for the Fiordland region.  

  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.  

  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.