Population sizes of light-mantled sooty albatross (Phoebetria palpebrata, LMSA) at the three New Zealand breeding sites (Auckland, Antipodes, and Campbell Islands) are poorly known. Annual counts since 1999 of a small number of LMSA nests show a long-term population decline on Adams Island, Auckland Islands. Mean nest numbers in 2016-17 were 10% down on counts in 1999–2000, with an annual rate of decrease, lambda, of 0.44 in the period 1999–2019. Three methods to estimate the breeding population size were trialled: ground counts of nests (Adams); aerial photography of LMSA with ground-truthing (Adams); and boat-based counts of LMSA on coastal cliffs (Campbell). Ground counts in a clearly delimited area were repeatable (42 and 40 active nests in 2017 and 2018, respectively), thus useful for monitoring, but ground counts are too limited for a whole-island population estimate. Aerial photography overestimated the number of active nests by 12.5% compared with ground counts. Ground-truthing showed that most apparently occupied nests contained an egg, and so nests occupied by birds with no egg are a smaller error source when interpreting aerial photographs than for other albatrosses. Boat-based LMSA counts proved inaccurate due to vessel movement. Considering that the terrain favoured by LMSA is very difficult to access, population size estimates based on aerial photography with ground calibration for apparent breeders appear the most effective of the techniques trialled. Ongoing counts at vantage-point and ground-count sites enable continued monitoring of LMSA trends at Adams Island.
Twenty-four breeding colonies of three petrel species were found on 18 of 26 islands surveyed in Breaksea Sound/Te Puaitaha, Fiordland National Park, New Zealand, in November 2017 and December 2019. All vegetated islands within Breaksea Sound were surveyed, along with 20 islands in Dusky Sound/Tamatea that were not included in an initial survey in November 2016 (eight of these additional Dusky Sound islands had breeding petrels, including three with broad-billed prions Pachyptila vittata). Sooty shearwater (Ardenna grisea) was the most widespread and abundant species in Breaksea Sound, with an estimated 6,950 burrows on 14 islands, while broad-billed prions were breeding on seven islands (2,100 burrows estimated). We record the first evidence of mottled petrels (Pterodroma inexpectata) breeding in Breaksea Sound, which is now their northernmost breeding location. Burrow occupancy rates were not assessed for any of the species. Most of the islands in Breaksea Sound had previously been surveyed during 1974 to 1986, before Norway rats (Rattus norvegicus) were eradicated from Hāwea and Breaksea Islands, and stoats (Mustela erminea) controlled to near zero density on Resolution Island and adjacent islands (including the inner Gilbert Islands and Entry Island). Following pest mammal control or eradication, broad-billed prions have colonised at least four additional sites. Sooty shearwaters were found at five sites in Breaksea Sound where they had not been recorded in 1980–83, and at one site they had increased by more than 50-fold since rat eradication. When combined with data from the 2016 and 2017 surveys, more than 75,700 petrel burrows are estimated to be present in southern Fiordland.
The Auckland Islands comprise the largest and most researched island group in the New Zealand subantarctic region, and have the largest number of endemic bird taxa. Paradoxically, they are the only one of the five island groups that has not yet been the subject of a comprehensive avifaunal review. We summarise the history of ornithological exploration of the group, and where this information is held, based on a database of 23,028 bird records made between 1807 and 2019. More than 76% of these observations were unpublished, with the two largest sources of information being Heritage Expedition wildlife logs (5,961 records) and records collected during the Second World War coastwatching ‘Cape Expedition’ (4,889 records). The earliest records of endemic taxa are summarised, along with the earliest records of significant seabird breeding colonies. Citizen science (principally eBird, with 1,597 unique records) is a rapidly growing source of information, and new records of vagrant species continue to accumulate at a rapid rate. Compared with other subantarctic islands, Auckland Islands’ birds have received very little research attention, with most effort to date focused on a few large surface-nesting seabird species.
Disequilibrium of bird communities, due to introduced pests and human-caused habitat changes, is a fundamental property to be understood in restoration of island biota. In this paper, we suggest that the reestablishment of native forests and food webs favour long-established and native species, and is less favourable to more recently introduced species. To test this hypothesis, we compared population trends of native and non-native birds on five islands in the Ipipiri Group in the north of New Zealand. We used over 900 station counts starting in 2008 when habitat recovery and pest (rat [Rattus], mouse [Mus musculus], and stoat [Mustela erminea]) removal began, as well as comparing to a set of earlier counts. In general, we found that detection rates of most long-established endemic native species significantly increased, while non-native species mostly decreased, suggesting population increases and decreases, respectively. Of the native species, six are relatively recent natural immigrants to New Zealand, and most of these declined or remained unchanged. We suggest that the increase in long-established natives is likely due to increased size and quality of native bush areas making habitat more favourable to these natives, as well as reduced predation and competition from the pest mammals.
During southward migration from Alaska in 2006, a satellite-tracked female bar-tailed godwit (Limosa lapponica baueri) encountered adverse weather and stayed between 19 September and about 28 September 2006 at Ouvéa (Loyalty Islands, New Caledonia), where she apparently died. Ouvéa was visited between 27 September and 7 October 2007 to look for godwits. A total of eight godwits was recorded of which one, thought to be an adult female, may have been a dropout migrant. The remaining birds appeared to be immatures.
The white-capped mollymawk (Thalassarche cauta steadi) and Tasmanian mollymawk (T. cauta cauta) have discreet breeding sites, but away from their breeding grounds, where their at-sea ranges overlap, they are difficult to identify. The bill colour of these taxa has recently been considered to differ, but there is much conflicting information in published accounts. Three key differences often discussed are the amount of yellow on the culminicorn, the amount of yellow on the cutting edge to the upper mandible, and the amount of darkness on the mandibular unguis. In January 2018 I assessed these characters in 100 adult white-capped mollymawks at their Disappointment Island breeding site and found that each character was variably present. The majority of white-capped mollymawks lacked a yellow base to their culminicorn and had a dark mark on their mandibular unguis. In contrast, it has been reported that the majority of adult Tasmanian mollymawks have yellow at the base of their culminicorn and lack a dark mark on their mandibular unguis. While these characters can be used as a guide to identify these taxa, a minority of individuals of each taxon show the ‘typical’ bill colours of the other taxon. The amount of yellow on the cutting edge to the upper mandible varied between individual white-capped mollymawks, and so this is not a useful identification character.
The foraging behaviour of two foliage gleaning birds, rifleman and grey warbler (henceforth warbler), was studied at Kowhai bush, Kaikoura, with the aims of exploring behavioural variation by individual pairs, and broader patterns of foraging behaviour for each species. Data on six foraging variables were collected from individually identifiable birds of known breeding status at the time of sampling. A total of 1,632 samples were taken during the spring/summer period of 1987/8. Data analysis explored foraging behaviour in relation to species, sex, and breeding stage. Individual pairs of riflemen exhibited significant variation in behaviour, indicating behavioural specialisation that I term a “foraging personality” identified as an emergent characteristic of each pair. Riflemen showed greater within-pair variation than warblers. The similarities and differences in foraging behaviour between the two species are described and are linked to their behavioural ecology. Analyses are presented in relation to the problem of data independence when repeated samples are taken from one individual.
Maungatautari is a 3,240 ha pest-fenced ecosanctuary free of virtually all mammalian predators in Waikato, New Zealand. We used triennial 5-minute counts within the ecosanctuary and biennial surveys of residents up to 20 km from the perimeter pest fence to measure spillover of tūī from Maungatautari into the surrounding area over a 9-year period (2006–2014) following pest eradication. Following pest eradication in the ecosanctuary, tūī relative abundance increased there and in the surrounding largely unmanaged area. The mean number of tūī per 5-minute count within the ecosanctuary was 2.23 (se = 0.163) in 2005 and increased following predator eradication in 2006 to 3.33 (se = 0.206) in 2008, 3.76 (se = 0.193) in 2011, and 2.68 (se = 0.279) in 2014. The mean maximum number of tūī at one time observed by residents in the largely unmanaged area increased from 4.4 (max = 47, n = 320) in 2006 to 15.6 (max = 300, n = 138) in 2014. Tūī numbers in both the ecosanctuary and the surrounding area were positively correlated with time since pest eradication. In the largely unmanaged area surrounding Maungatautari, tūī numbers were also positively correlated with provision of artificial food, and negatively correlated with distance from the ecosanctuary. Wind was negatively correlated with the number of tūī recorded in 5-minute counts at Maungatautari. Our findings show that pest-free ecosanctuaries can facilitate increased abundance of volant birds in surrounding landscapes if habitat is available.
We report Records Appraisal Committee (RAC) decisions regarding Unusual Bird Reports received between 1 January 2017 and 31 December 2018. Among the 160 submissions accepted by the RAC were the first New Zealand records of Macquarie Island shag (Leucocarbo purpurascens) and Cox’s sandpiper (Calidris x paramelanotus), and the first accepted at-sea sightings of blue petrel (Halobaena caerulea), Salvin’s prion (Pachyptila salvini), Antarctic prion (P. desolata), and thin-billed prion (P. belcheri) from New Zealand coastal waters. We also report the second accepted breeding record (and first successful breeding) for glossy ibis (Plegadis falcinellus), and the second accepted records of red-footed booby (Sula sula) and laughing gull (Leucophaeus atricilla). Other notable records included the first record of nankeen kestrel (Falco cenchroides) from Campbell Island, and at least 5 northern shovelers (Anas clypeata) simultaneously present in June 2018.
Rotuma, Fiji, is a small and isolated island in the Central Pacific, rarely visited by ornithologists. We present here our own observations on the avifauna, obtained in 1991 and in 2018, completed by previous records obtained since the 19th Century. The main changes on the species composition concern the extirpation of the white-throated pigeon and the settlement of the reef heron. The status of the four endemic landbirds (one species and three subspecies) is good, especially that of the Rotuma myzomela. However, the recent arrival of the common myna (2017–2018) represents a potential threat. We also observed that the Pacific sheath-tailed bat, which was abundant 30 years ago, has probably been extirpated from the island.