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.