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.
This paper presents the results of four censuses of the northern New Zealand dotterel (Charadrius obscurus aquilonius) population undertaken between 1989 and 2011. During that period, the population increased by roughly 50%, from about 1,320 to about 2,130 birds. Most birds (85%) were in the northern part of the North Island (Northland, Auckland, and Coromandel Peninsula), but the taxon is expanding its range southwards on both the west and east coasts. On the east coast, a few pairs are now breeding close to Cook Strait. Population trends varied between regions, and almost all of the overall increase was a result of increases on the east coast. The highest rates of increase were on the Auckland east coast and on Coromandel Peninsula, probably because the intensity of management has been highest in those regions. In the Auckland urban area, birds now routinely breed inland, mainly on grass or bare earth; elsewhere, the taxon is almost entirely coastal. The proportion of birds on the west coast has fallen over the past 50 years, and about 85% of the taxon is now found on the east coast. If the overall increase in numbers has continued at the same rate since 2011, there would be about 2,600 birds in 2020. The size of the population and its rate of increase justify the recent down-listing of the subspecies to a threat ranking of At Risk (Recovering), but it remains Conservation Dependent. The recovery programme has been highly successful, and most management of the taxon is now undertaken by community groups, regional councils, and volunteers. Continuing threats include predation, flooding of nests, and disturbance during breeding; in future, continuing coastal development and increased recreational activity will probably degrade habitat further, particularly on the east coast, and climate change will have a range of impacts.
Co-ordinated counts of waders across New Zealand have been undertaken in November and June since 1983; the consistent timing of counts aimed to reduce variation from the effect of seasonal changes in bird numbers. The Australian Shorebird census and the wider Asian Waterbird Census, however, are conducted in January, making direct comparison with the New Zealand counts potentially problematic, especially if an attempt is to be made to assess total flyway populations. Since 1998 waders on Farewell Spit (40°30.5 ́S, 172°45 ́E to 40°33.5 ́N 173°02 ́E) have been counted in February as well as in November and June. Counts of bar-tailed godwit and ruddy turnstone were on average 20% and 35% higher in February compared to November, respectively. Also, counts of the endemic migratory South Island pied oystercatcher were 15% higher in February compared to June. The improvement of data for overall population assessments is not only important for establishing trends of species but is also important for applying the 1% population criterion for wader site assessments.
Two approaches to estimating the population size of great albatrosses (Diomedea spp.) were tested in the Auckland Islands, New Zealand. The first approach used a series of aerial photographs taken on Adams Island to produce high-resolution photo-mosaics suitable for counting nesting Gibson’s wandering albatross (Diomedea antipodensis gibsoni). The second involved a direct count from a helicopter of southern royal albatross (D. epomophora) breeding on Enderby Island. Both techniques produced results that closely matched counts of albatrosses attending nests derived from ground counts, although aerial counts could not determine whether birds were sitting on eggs or empty nests. If estimates of breeding pairs are required, aerial counts of nests require a correction factor to adjust for birds that are apparently nesting but have not laid. Such correction factors are best based on ground counts undertaken simultaneously with the aerial counts. Used in conjunction with correction factors, the two techniques provide a method of estimating the population size of great albatrosses breeding in remote areas where it may be logistically difficult to undertake ground counts of the whole population.
Between 2010 and 2016, the community group Friends of Flora Inc., in partnership with the Department of Conservation, translocated 44 roroa (Apteryx haastii) to the Flora Stream area in Kahurangi National Park, New Zealand. Each kiwi was fitted with a VHF transmitter and their subsequent locations were monitored for two to eight years by radio-telemetry. Monitoring showed that short to medium term translocation goals relating to survival and home range establishment were met. Dispersal occurred for 9 to 878 days prior to home ranges being established. This post- translocation monitoring was used to inform management decisions to extend predator control from 5,000 to 9,000 ha and to retrieve four of the kiwi that dispersed outside the project area. At the end of the study, 68% of the translocated kiwi were known to have home ranges within the trapped area. The study illustrates the benefit of long-term post- translocation monitoring and a flexible approach to deal with unforeseen dispersal.
Many species recovery programmes use pedigrees to understand the genetic ancestry of individuals to inform conservation management. However, incorrect parentage assignment may limit the accuracy of these pedigrees and subsequent management decisions. This is especially relevant for pedigrees that include wild individuals, where misassignment may not only be attributed to human error, but also promiscuity (i.e. extra-pair parentage) or egg-dumping (i.e. brood parasitism). Here, we evaluate pedigree accuracy in the socially monogamous and critically endangered kakī (black stilt, Himantopus novaezelandiae) using microsatellite allele-exclusion analyses for 56 wild family groups across three breeding seasons (2014–2016, n = 340). We identified 16 offspring where parentage was incorrectly assigned, representing 5.9% of all offspring. Of the 16 misassigned offspring, three can be attributed to non-kakī brood parasitism, one can be assigned to human error, but others cannot be readily distinguished between non-monogamous mating behaviours and human error. In the short term, we advise the continued use of microsatellites to identify misassigned offspring in the kakī pedigree, and to verify non-kakī brood parasitism. We also recommend the Department of Conservation’s Kakī Recovery Programme further evaluate the implications of pedigree error to the management of this critically endangered taonga species.
Bar-tailed godwits (Limosa lapponica) were counted throughout New Zealand and on the east coast of Australia during the 2019–2020 austral summer, in the first attempt to assess the total population of the subspecies baueri on the southern hemisphere non-breeding grounds. Survey coverage in New Zealand was nationwide (158 sites surveyed); surveys in Australia covered 314 sites between Great Sandy Strait in southern Queensland, and the Gulf St Vincent in South Australia. Areas north of Great Sandy Strait were either partially counted or were not visited over this survey period. Partial surveys were excluded from the survey results. The total number of godwits counted was 116,446. If allowance is made for an additional ~10,000 birds expected to have been present in northern Queensland (based on previous surveys), the total population of baueri in New Zealand and Australia would have been about 126,000. The 2019 breeding season was very successful, with the highest recorded number of juvenile birds since 2011 and 2012.
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.
Little penguins (Eudyptula minor) readily breed and moult in nest boxes. The selective placement of nest boxes can enhance their use, improve breeding success and increase recruitment. I examined nest parameters for 171 nest boxes at Pilots Beach, southern New Zealand, in relation to their use for breeding and for moulting in the 2016 breeding season. Linear models to assess the relative importance of nest box parameters produced definitive results where a higher likelihood of use was interpreted to indicate a preference. The only preference for breeding or moulting was for shaded boxes that were free of vegetation at ground level. These trends were supported by comparisons of proportions of boxes used for breeding and moulting that indicated shaded boxes surrounded by bare ground were preferred to unshaded boxes surrounded by introduced grasses. Proportions also indicated that boxes on flat ground with a flat entrance were preferred to boxes on sloped ground or a sloped entrance for breeding and moulting. About half of the boxes between 61 and 90 m distance to the landing were used for breeding and moulting. Females nesting in shaded boxes had a higher breeding success than those in unshaded boxes but their chick masses were similar. To optimise nest box use by little penguins and encourage recruitment, nest boxes ideally should be placed under bushes or artificial structures on open ground up to 90 m from the landing.