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.
Abstract: Observations were made of the Nationally Vulnerable Hutton’s shearwater (Puffinus huttoni) breeding at Te Rae o Atiu, Kaikōura Peninsula (42.429°S, 173.703°E), New Zealand, a new colony established by translocations where birds breed in nestboxes. Over 12 seasons there were 245 eggs laid, including seven instances of two eggs laid as separate clutches in one nestbox during the same season. Nestbox inspections, usually undertaken weekly, provided evidence of egg laying date. Bird attendance at the nestboxes was also obtained from implanted passive integrated transponders that triggered a reader and datalogger. There is evidence for birds re-laying an egg after the first egg failed for three separate events, and a fourth was a possibility. In three other events, it appears more likely that two different birds laid the eggs, two as female-female pairings or simply egg dumping by an unpaired female; the third event was inconclusive. Only one of the 14 eggs from two-egg nests hatched, and the chick fledged successfully, about 10 days later than any other chick recorded at this colony. This fledging date was similar to the last date for fallout birds from the natural, mountain colonies, and suggests that re-laying may be a natural consequence of early egg failures in this species.
Since the publication of the fifth edition of the Checklist of the Birds of New Zealand in 2022, 3 new vagrant species (2 terns and a storm petrel) have been accepted as occurring in New Zealand as at 31 December 2023, and 11 species that became extinct more than c. 1 million years ago have been described. These comprised 3 waterfowl, 1 owlet-nightjar, 1 tropicbird, 3 penguins, 1 albatross, 1 petrel, and a ‘false-colie’ (the latter is considered unrelated to any known group of birds). These 11 new fossil species were found in deposits of the following epochs: Paleocene (3), Miocene (6), and Pliocene (2). The richest areas for discovering new species were Miocene lacustrine deposits of the St Bathans region of Central Otago (5 species), and Paleocene marine deposits from the eastern South Island (3 species). Two Pliocene seabirds were from marine sediments in south Taranaki, and a Miocene albatross was found in a limestone quarry in South Canterbury. Recent publications potentially affecting the taxonomy, nomenclature, classification and arrangement of New Zealand birds are assessed, and recommendations are made that affect 56 taxa. This includes splitting Tibetan sand plover Anarhynchus atrifrons from Siberian sand plover A. mongolus, and Pyramid prion Pachyptila pyramidalis from fulmar prion P. crassirostris, thereby adding a further two species to the New Zealand bird list. The total number of bird species, including fossil species, now accepted from the New Zealand region is 502.
The wrybill | ngutu pare (Anarhynchus frontalis) is a small plover endemic to New Zealand with a unique laterally curved bill. Apart from moult, much of its biology is well understood: adults breed from late August to January on the braided river systems in Canterbury and inland Otago on New Zealand’s South Island. From midsummer, late December and January, they migrate north to non-breeding areas in the northern part of the North Island, especially to the large tidal bays, east and west of Auckland, where they undergo primary moult from January to April. The Underhill- Zucchini moult model was used to estimate the mean start and completion dates of primary moult, which were 20 January and 3 April respectively. Adults thus commence primary moult soon after arrival on non-breeding grounds but complete moult around four months before southward migration to their breeding areas in August. They appear to avoid primary moult during winter. Second-year birds start primary moult in December, one month earlier than the adults, but finish at approximately the same time. Primary moult of the wrybill is compared with closely related species, and with other waders that breed on the South Island and migrate to North Island for the non-breeding season.
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).
Holdaway, R.N.; Allentoft, M. E. 2022. A basic statistical approach to determining adult sex ratios of moa (Aves: Dinornithiformes) from sample series, with potential regional and depositional biases. Notornis 69: 158-173.
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.