Publications Archive

Abstract: A new colony of the endangered Hutton’s shearwaters (Puffinus huttoni) has been established at Te Rae o Atiu on the Kaikōura Peninsula, South Island east coast, New Zealand to provide insurance against catastrophic events at the high-altitude natural colonies in the Kōwhai River and Shearwater Stream, Seaward Kaikōura Range. The translocation of 495 chicks from the Kōwhai River colony was carried out in six operations from 2005 to 2013. Of the 473 fledglings, 97 have been recorded back at Te Rae o Atiu. Chick selection criteria, fledgling mass, fledgling wing length, days present before fledging, and days of emergence before fledging had no bearing on whether chicks returned from their post-fledging migration to Australian waters or not. One hundred and twelve Te Rae o Atiu bred chicks have fledged up until 2020–21. The Te Rae o Atiu fledglings had similar mass and wing lengths, and days emerged prior to fledging, to the translocated fledglings. There were no differences between the groups of Te Rae o Atiu bred birds that returned or did not. At 2020–21, 21 of the 112 second-generation chicks have returned from their initial migration, and the earliest have bred successfully. The colony has grown to about 75 birds producing about 30 eggs, 24 chicks, and 22 fledglings annually. Future growth of Te Rae o Atiu will be reliant on these home-bred chicks as the oldest translocation birds will soon be approaching the end of their breeding lives. Acoustic attraction of birds flying over Te Rae o Atiu from the sea towards the Kōwhai River natal colony has been mostly unsuccessful with only two birds attracted.

Abstract: Captive facilities across New Zealand strive to mimic natural conditions for captive animals as closely as possible. In the case of the kiwi (Apteryx spp.), captive habitats are augmented with natural stimuli such as soils, leaf litter, bark, plants, logs, and mosses. Interaction with these introduced stimuli has been shown to encourage normal foraging behaviour and is speculated to aid in inoculating young animals with healthy microbial communities. However, introducing non-sterile natural stimuli into the captive environment also carries the risk of exposing kiwi to diseases such as aspergillosis, coccidiosis, and candidiasis. Aspergillosis is of particular concern to rearing facilities – the disease is most commonly attributed to exposure to Aspergillus fumigatus, an opportunistic fungal pathogen. Here we present a PCR-based screen to qualitatively detect the presence and/or absence of A. fumigatus in soils. Soil samples collected from nesting sites of rowi (Ōkārito brown kiwi, Apteryx rowi) in the Ōkārito region of the West Coast were screened for A. fumigatus using a species-specific primer set coupled with a basic DNA extraction. Willowbank Wildlife Reserve soil and substrate samples were also screened as a baseline comparison representing captive rearing facilities. Results from the assays showed that the extraction technique was effective at isolating A. fumigatus DNA at detectable levels from a variety of soils, and that Ōkārito soils did not harbour a higher abundance of A. fumigatus than those found at Willowbank. This preliminary screening method could be used by facilities in New Zealand to quickly and cheaply screen soils and substrates for A. fumigatus before introducing them to captive enclosures.

Abstract: The critically endangered kuaka Whenua Hou (Whenua Hou diving petrel, Pelecanoides georgicus whenuahouensis) is a burrow-nesting petrel, restricted to breeding in the foredunes of Whenua Hou. The species’ recovery is inhibited by ongoing threats such as vessel-based light pollution, interspecific competition, and climate change including storm-induced erosion of fragile breeding habitat and thus, kuaka Whenua Hou would benefit from the establishment of a new colony through translocation. However, translocations of petrels require hand-rearing of pre-fledging chicks on the destination site to reset their philopatric behaviour. We documented a hand-rearing and translocation trial of kuaka Whenua Hou in preparation for future translocations. Ten kuaka Whenua Hou chicks were translocated from natal burrows to nest boxes installed behind the colony, and hand-reared on a bespoke diet of pureed sardines. All hand-reared chicks fledged successfully, with fledging mass similar to naturally-reared chicks and with slightly longer wing lengths. The techniques used highlighted the importance of selection criteria, access to natural growth curves to infer feeding regimes, nutritionally rich diets, and strict hygiene protocols. Our trial provides a knowledge base for future translocations and the establishment of new kuaka Whenua Hou colonies.

Tuhinga whakarāpopoto: He momo tata korehāhā te kuaka o Whenua Hou (Pelecanoides georgicus whenuahouensis), he momo ōi e whai rua hei kōhanga, kua mau ki te whakatipu ki ngā tāhuahua kopī o mua o Whenua Hou. Ko te whakarauora o tēnei momo kua whakanguengue i ngā āhuatanga whakaraerae e mau tonu pērā i te pokanga rama, ā rātou ake pakanga ki a rātou me te hurihuri o te āhuarangi, tae noa atu ki te horonga whenua o te pūrei kōhanga marore nō te marangai, ā nō reira, ka whai hua te kuaka Whenua Hou i te whakatūtanga atu o tētahi taiwhenua hou mā te nukunuku kōhanga. Engari, me whakatipu ngā pīrere ki te ringa ki te wāhi e tū ai te kōhanga hou kia ea ai te nuku kōhanga, ā, kia tautuhi anō tā rātou hiahia ki te hoki atu ki te kāinga i whakatipuria kētia rātou. I āta mārama mātou ki te whakamātautau o te whakatipu ā-ringa me te nukunuku kōhanga o te kuaka Whenua Hou kia whakarite ai ki te nukunukunga tūturu e haere ake nei. I nuku kia ngahuru ngā pīpī kuaka Whenua Hou mai i ngā rua i whānau mai ai rātou ki ētahi kōhanga hanga i whakatūria ki muri i te taiwhenua matua, ā, i whakatipuria rātou ki te ringa ki ētahi kai ake o te hārini penupenu. I whai huruhuru pai ngā pīpī katoa, ā, ehara i te rerekē te taumaha o ēnei pīpī i ērā i whakatipuria ki ō rātou ake kōhanga, engari he paku roa ake ngā parirau. I whakamiramira atu ngā tū-āhua i whakamahia i te hiranga o ngā paearu whiri, te whai wāhitanga ki ngā pikinga whakatipu māori kia whakapae tika ai te tikanga whāngai, te whiringa o te kai taioranga me ngā tikanga akuaku mārō. Ka noho tā mātou whakamātautau hei tūāpapa mātauranga ki ngā nukunukunga kōhanga e haere ake nei, me te whakatūtanga o ētahi taiwhenua hou mō ngā kuaka Whenua Hou.

Abstract: There is limited information available on how New Zealand wetland bird communities respond to removal of mammalian predators, and reintroduction of locally extinct species. The forested Zealandia Te Māra a Tāne sanctuary in Wellington is surrounded by a mammal predator-exclusion fence, and contains two small lakes (2.7 and 1.1 ha). Counts of all visible wetland bird species were used to assess changes in the Zealandia wetland bird community over 28 years. This included a 3-year block of counts before the fence was built in 1999. Flocks of up to 143 southern black-backed gulls (karoro, Larus dominicanus) bathed on the larger lake before the catchment was opened to the public after 1999. Brown teal (pāteke, Anas chlorotis) and New Zealand scaup (pāpango, Aythya novaeseelandiae) both established resident breeding populations following releases of captive-reared birds between 2000 and 2003. Little shag (kawaupaka, Microcarbo melanoleucos), black shag (māpunga, Phalacrocorax carbo) and pied shag (kāruhiruhi, P. varius) all colonised naturally, and started breeding in 2003, 2008, and 2009 respectively. Paradise shelducks (pūtangitangi, Tadorna variegata) increased after the sanctuary was created, although numbers remained small (mean counts of c. 5 birds). Numbers of mallards (Anas platyrhynchos) were unaffected by creation of the sanctuary; however, there was an unexplained decline after 2016. Overall, the wetland bird community in Zealandia has become more diverse over time, and with a higher proportion of native and endemic species. However, we suggest that some of these changes (particularly the establishment of a large breeding colony of pied shags) might well have occurred even if the sanctuary had not been created.

Abstract: Across all bird species, latitude plays an important role in determining patterns in timing, duration, and synchronisation of primary moult but, apart from Africa, moult studies at the southernmost limits of the continents and islands in the southern hemisphere are lacking. The focus of this study is the self-introduced silvereye (tauhou, Zosterops lateralis) in New Zealand, one of the most southern countries in the world. Moult data collected by bird banders during the period 1978–2022 were analysed using the Underhill-Zucchini moult model. Silvereyes had an estimated primary moult duration of 74 days, with a mean population start date of 3 February and a mean completion date of 19 April. Post-breeding primary moult in adult silvereyes starts soon after the breeding season and ends shortly before some of the more southern birds embark on their seasonal northward migratory movements. Juvenile primary moult is estimated to start approximately two weeks after the start of post-breeding moult in adults. A literature review suggested that primary moult duration for Zosterops species is similar regardless of latitude, but the timing of moult is variable and adjusted to local conditions.

Abstract: Tree martins (Petrochelidon nigricans) are vagrants to New Zealand from Australia, with the first record in 1851. However, there is some doubt as to whether every tree martin historical record can be assigned to this species, with the now-established welcome swallow (Hirundo neoxena) a likely confusion species. Records of tree martins and other hirundines were examined against historical record criteria in order to establish an accurate picture of past tree martin vagrancy. Forty-eight relevant records (1851–1978) were collated and reviewed. It was considered that 16 records were probable or confirmed tree martins, 19 were possible tree martins, and just three were possible welcome swallows. The remaining ten records were classified as unidentifiable, with most of these lacking descriptions. Only four 19th century tree martin records should be verified. None of the many 1892–93 hirundine invasion records could be certainly assigned to any particular species. Considering the tree martin was more frequently recorded, it is perhaps surprising it is the less successful colonist of the two species.

Abstract: The black-winged petrel (Pterodroma nigripennis) is an abundant procellariiform seabird breeding on islands in the Southwest Pacific and Indian Oceans. The largest populations breed in the New Zealand region where at sea movements and breeding behaviour across the annual cycle remain poorly described. We used geolocators with saltwater immersion sensors to track movements and characterise breeding behaviour of P. nigripennis from three New Zealand breeding colonies (Raoul, Burgess, and Rangatira Islands) across a 1,600 km latitudinal gradient. Breeding extended from November to June and in Raoul Island birds pre-laying, incubation, and chick rearing periods lasted 36, 50, and 85 days respectively. During breeding, birds from all colonies foraged within waters of the subtropical convergence zone which for Raoul, required one-way foraging trips of over 1,500 km. During March–June birds migrated east, then north and northwest to core foraging zones predominantly within the North Pacific subtropical front, but a small number of birds also wintered south of Hawaii in equatorial waters. Birds were predominantly nocturnally active during breeding and non-breeding seasons indicating a dependence of nocturnally available prey. These data contribute to a growing understanding of the unprecedented movements and potential partitioning of habitat by Australasian Pterodroma petrels within the Pacific Ocean and we summarise and discuss available data.

Abstract: Procellariiform seabirds are vulnerable to numerous threats, including the growing issue of urban light pollution. Seabirds that are found grounded are often treated by avian/wildlife rehabilitation centres, but approximately 30% do not survive. Here, we necropsied 19 grounded Cook’s petrels (tītī, Pterodroma cookii) that did not survive and report the cause of death and injuries. We also investigate potential risk factors, including association with light pollution, seabird sex, age, and sensory features. We found that a 70% of Cook’s petrels had head trauma, internal bleeding, and/or wounds as the main causes of death (p > 0.05). These injuries are consistent with collisions, likely due to disorientation from light pollution. Most Cook’s petrels were not stressed or in poor body condition, suggesting Cook’s petrels are typically healthy before being affected by lights. In the sample of Cook’s petrels studied, mortality was significantly biased towards young and male seabirds. Despite this apparent sex difference in collision risk, there was no detectable sex difference in measured sensory features, e.g. males did not have significantly larger eyes than females. The potential sex bias in death suggests male seabirds could be more vulnerable to light pollution, which warrants further research. Further research is also required to determine whether individual differences in sensory features relate to grounding risk, as our study only included a subset of dead seabirds. We also recommend that all grounded seabirds are taken to rehabilitation centres rather than released immediately.