Publications Archive

A total of 15,694 black-billed gulls (tarāpuka, Chroicocephalus bulleri) chicks were banded at six braided gravel-bed rivers in North Canterbury, New Zealand, from 1958 to 1983, and at least 1,754 later sightings of dead or alive birds were reported to the Banding Office. The main banding sites were the Ashley River and its major tributary, the Ōkūkū River; other banding was carried out on the Kowhai River near Kaikoura, Conway River, Waiau River, Waipara River, and Waimakariri River. Colonies typically shifted location between years, as flooding and weed growth affected the habitat and suitability for nesting. Up to 6 colonies were found on the Ashley River system in a season. Average size of all colonies was about 230 nests, with the largest reaching about 800 nests. Some birds were found at rivers apart from their natal rivers. Birds bred when as young as 2-years-old. The furthest sighting was at Firth of Thames, 736 km NE of the banding site; the southernmost was at Waipahi, Otago, 412 km SW of the banding site; and the oldest recovery was 22.1 years after banding. Band loss likely affected recovery rates, as the oldest bird found with an aluminium band was only 10.9 years-old.

Rapa Island, located in Eastern Polynesia, hosts 12 species of breeding seabirds, now primarily found on its ten peripheral islets. These seabirds face various threats, such as invasive mammals that prey on eggs and chicks, as well as invasive plants that encroach upon and degrade their breeding habitats. Major island restoration projects are currently underway on several islets, focusing on the removal of invasive mammals and plants. We present data collected here between 2017 and 2024 and, together with published and unpublished surveys since 1921, compile details on the distribution, population, and breeding seasons of these seabird species.

This paper describes North Island kokako (Callaeas wilsoni) recovery actions and outcomes since 2000 at 11 sites with relict populations, and at 12 other mainland and three offshore island sites to where they have been translocated. Populations are now secure on pest-free Te Hauturu-o-Toi / Little Barrier Island and Kapiti Island, and Tiritiri Matangi Island is a valuable advocacy site. Maungatautari is a large (3,300 ha) pest-fenced and pest-free site that has demonstrated rapid kōkako recovery. All other sites are unfenced and require ongoing control of key pests. The national total of kōkako pairs has increased from c. 458 in 2000 to c. 2,327 in 2023; however, latest counts indicate populations at seven sites have declined. Future kōkako recovery will be assisted most by improved, large-scale pest control tools for unfenced mainland sites, and by sustained effective pest control in large key relict populations (Pureora, Te Urewera, Rotoehu, Mapara, and Mokaihaha).

Te Araroa Trail runs for more than 3,200 km between Cape Reinga and Bluff, along the length of Aotearoa New Zealand’s two main islands. All birds seen and heard along the trail during the austral summer were counted in 1,720 contiguous transects during 124 days of walking from north to south between 2 November 2023 and 11 March 2024 (84.7% of transects were 2 km long). A total of 106,207 birds of 107 species were counted during daylight transects, at a mean encounter rate of 32.6 individuals per km. The highest counts were for house sparrow (Passer domesticus – 12,517 birds), chaffinch (Fringilla coelebs – 5,806), and red-billed gull (Chroicocephalus novaehollandiae – 5,427). The species recorded most frequently were chaffinch (62.3% of transects), silvereye (Zosterops lateralis – 58.5%), and Eurasian blackbird (Turdus merula – 56.7%). Bird communities are summarised and compared for 19 sections covering the entirety of the trail, providing a baseline for comparisons within regions and over time. Northern and/or southern limits are presented for 30 species with restricted distributions. Comparison of counts along sections of the trail that were trapped (233 km, including 22.4% of forest) with counts from untrapped forest sections revealed that tūī (Prosthemadera novaeseelandiae), kererū (Hemiphaga novaeseelandiae), and New Zealand fantails (Rhipidura fuliginosa) were more abundant where predator control was undertaken. Twenty of the fantails seen in the South Island were black morph (5.6%), with the remaining 339 (94.4%) pied morph, indicating that the proportion of black morph birds has been stable over the past two decades. In addition to describing bird communities likely to be encountered on different sections of Te Araroa Trail, this account (and the dataset it is based on) provides a baseline for comparing New Zealand bird communities over time and space.

A colony of the Nationally Vulnerable Hutton’s shearwater (Puffinus huttoni) was established by translocations to Te Rae o Atiu, Kaikōura Peninsula from 2005. Weekly observer visits to the wooden nestboxes, and records from passive integrated transponder readers, provided detailed records of breeding activity. Birds visited many nestboxes in a season, with up to 29 birds recorded at one nestbox, and one bird recorded at 23 nestboxes. Breeding started at 4 years for males and 5 years for females. The pre-laying exodus by females averaged 11.8 days; however, there were instances of birds making up to three brief visits back to the colony. Egg laying was usually on the night of arrival back from the pre-laying exodus, and was asynchronous — average 6 November, but as late as 25 December. There were seven instances of two eggs being found in a nestbox in one season, with evidence of relaying in at least one case. The average hatching date was 13 December, incubation averaged 52 days, with a mean hatching success of 58%. Fledgling period was 87 days on average, with a mean success of 88%, resulting in mean productivity of 52%. Chicks left nestboxes on average 8 nights before fledging, before their first migration to Australian waters. Adults stopped visiting the nestboxes on average 17 days before their chicks fledged for females and 8 days for males. Fledging mass averaged 415 g, 75% of the mean peak mass of 550 g. Single parents successfully fledged a chick when the mate was lost or ceased visiting for up to 71 days before fledging, and a light mass chick (310 g) returned to Te Rae o Atiu and paired up. Divorce occurred in 36% of pairings that did not end with the loss of a partner; 87% of birds had at least one divorce, and one bird lost one mate and divorced six times in 13 years. Nestbox fidelity showed changes by many pairs, especially if there has been a change of partner.

Buller’s albatross Thalassarche bulleri is generally considered to comprise two subspecies: T. b. bulleri, which breeds on islands south of the South Island, New Zealand; and T. b. platei, which nests on the Three Kings Islands, off the northern tip of of the North Island, and on outlying islets of the Chatham Islands east of New Zealand. Although the name platei has been widely applied to the latter population, some authors have suggested that its type specimen is in fact a juvenile T. b. bulleri. As a result, those birds breeding in the Chatham and Three Kings groups have sometimes been considered to represent an unnamed subspecies, or even species, given recent evidence of their genetic differentiation. Because our own morphological examination of the specimen was inconclusive as to which population the type of platei belongs, we subjected the individual to molecular testing. From this, we can confirm that the name platei has been correctly applied to the northern population of Buller’s albatross.

The distributions of birds on the islands of Aitutaki were surveyed 3–13 Oct 2024. We describe 22 resident and migratory species across the 17 islands of the almost-atoll Aitutaki, with regionally important colonies of red-tailed tropicbirds (Phaethon rubricauda), red-footed boobies (Sula sula), and wedge-tailed shearwaters (Ardenna pacifica), as well as a population of the IUCN-vulnerable blue lorikeet (Vini peruviana)on Aitutaki’s main island. While Pacific rats (Rattus exulans) and cats (Felis catus) are present on some islands, others potentially remain rat-free. Over the last 25 years, the reef island of Motukitiu has undergone a substantial habitat transformation from introduced coconut forest to native atoll broadleaf forest, enabling the recovery of seabirds.  Prevalent threats to the birds of Aitutaki include the introduction of additional rat species, spread of Pacific rat to currently rat-free islands within the almost-atoll, unsupervised tourism, and habitat modification on the small islands.

Albatrosses and petrels are among the most endangered seabird species worldwide. They face threats such as plastic ingestion, bycatch in fisheries, invasive predators at breeding sites, light pollution, and climate change. Many seabird species from Aotearoa New Zealand migrate to the eastern Pacific waters during the non-breeding season, following the abundant food availability of the Humboldt current. In this article, we compile observations of Thalassarche and Procellaria petrels in Ecuadorian waters from five information sources such as incidental tourist vessel observations, incidental fishermen observations, beach patrols, seawatching and GLS loggers. We provide strong evidence of the presence of Salvin’s albatross and White-chinned petrel in Ecuador, two species previously considered hypothetical for the country’s official bird list. Additionally, we present photographic evidence of a live Southern Buller’s albatross in Ecuador and document further observations of the black petrel, including its interactions with local fisheries. These records emphasize the importance of enhancing monitoring efforts to gain a deeper understanding of the ecology and conservation of Ecuador’s seabirds. They also highlight the necessity and advantages of collaboration between New Zealand and Ecuador concerning highly mobile bird species.

Kawau pāteketeke | New Zealand king shag (Leucocarbo carunculatus) nest occupancy, breeding, and offspring survival was studied for the first time at four colonies in 2018 and 2019, by analysing field camera still images. Nesting territories were retained year-round. Nest-building was underway by Mar and observed through much of the year. Successful pairs with stable nests were elevated and central to nest areas. Inter-colony asynchronous first clutches occurred over six months, with laying spanning 5–10+ weeks at single colonies (2019). Clutches of 2–3 eggs took ≤13 days to complete. Incubation commenced with first eggs; asynchronous hatching was 28–32 days later with brood reduction at early nestling stage and occasional replacement clutches observed. Chicks were unattended at 3–4 weeks, showing strong creche behaviour thereafter, and were fully feathered at 65 days, fledging soon after. Breeding outcome was most influenced by height above sea-level (waves), exposure (weather), and boat/landing disturbance. Most young disappeared from images at 4.5–5 months, their fate—dispersed or perished—unknown. Some resided at the colony into/ beyond the subsequent breeding season, sometimes interacting with presumed parents. Any predation (by gulls) was seen as opportunistic during disturbances, or of eggs not in nests.

Egg floatation is a technique which can be used to estimate egg age and hatching dates of New Zealand shorebird eggs. It can be used to improve the accuracy of nest survival models, help identify nest outcomes, assist with chick survival monitoring and to prioritise the capture of incubating birds. We used egg floatation to estimate the age and hatching dates of South Island pied oystercatcher (Haematopus finschi) (SIPO) eggs. We developed regression equations to estimate the age of SIPO eggs by modelling egg angle and egg float height against egg age using a sample of eggs with known hatch dates. For early incubation eggs, we used linear regression to model the relationship between egg age and egg angle only, whereas for late incubation eggs we used multiple regression to model the relationship between egg age and both egg angle and egg float height data. These equations allowed 90% of SIPO eggs to be aged to within five days of their actual age. We recommend that species-specific regression equations describing the relationship between egg float characteristics and egg age be developed for other New Zealand shorebird species, to aid future research, monitoring and conservation management actions on these species.