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.
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.
Four New Zealand pipit nesting attempts were monitored in an urban wasteland field in Onerahi, Whangarei.A female laid two clutches in dense kikuyu (Pennisetum clandestinum) in October and December 2015 and fledged young from both clutches. Pipits were then absent from the site from February until late August 2016. The male reappeared and used the exact same home range, with a new female. This female laid two nests in the more open low gorse (Ulex europaeus) and aristea (Aristea ecklonii) cover in September and October 2016 but both nests were depredated at 3–5 and seven days after hatching, respectively. All three chicks, the female, and possibly the male were killed during the latter predation event. There were differences in adult behaviour throughout the breeding cycle. The female constructed the nest and undertook all the incubation. During the incubation period the male was only present at the nest site in the early morning and did not roost at the site each evening. The pair was present throughout the day after the chicks hatched. Pipits used more frequent calling rates when there was a perceived threat, and when that threat was near a nest.
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.
Black-fronted terns (Chlidonias albostriatus) are globally endangered and are one of six endemic bird speciesthat rely on New Zealand’s braided river ecosystems for breeding. Like other marsh tern species, black-fronted terns are predicted to have low breeding-site fidelity due to the instability of their breeding habitat, small colony sizes and high predation rates. We used breeding colony location data collected from nine South Island rivers for 3–12 years (2004–2015) to investigate the breeding-site fidelity in black-fronted terns. The distribution of breeding colony locations from seven of the nine rivers analysed were not significantly different to a simulated random distribution. The tendency of blackfronted terns to form breeding colonies near past breeding site compared to new sites was only significant for two of the nine rivers analysed. Overall, there was low breeding-site fidelity in black-fronted tern colonies from year to year across the rivers analysed.
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.
The monitoring of animal populations is essential for reporting on the state of the environment, with birds often used as indicators of ecosystem health. Traditionally, bird monitoring has been done by field observers; however,there has been recent interest in use of automatic recording devices (ARDs) as an alternative. A monitoring programme managed by the New Zealand Department of Conservation (DOC), used observers and ARDs concurrently for three survey seasons, providing the opportunity to compare results in terms of effectiveness and efficiency. The difference in species-richness estimates from the two methods was small, with the observer method detecting slightly higher numbers of species in all habitat types. Detection probabilities for individual species, derived from occupancy analysis, were similar between methods, with a few exceptions: bellbird (Anthornis melanura), brown creeper (Mohoua novaeseelandiae), tūī (Prosthemadera novaeseelandiae), North/South Island robin (Petroica longipes/australis), and rifleman (Acanthisitta chloris). Bellbird and rifleman had a higher probability of being detected by ARDs, whilst the remainder were more likely to be detected by observers. Differences in detection probability may be due to identification confusion in the case of bellbird and tūī, and observer ability to detect and identify birds visually for brown creeper and North/South Island robin. The relationship between indices of abundance from the observer and ARD methods varied between species and habitat types. These inconsistencies suggested that the ARD results did not correlate closely with observed abundance, which may limit the ARD method to provision of confirmed presence data. Observer counts proved to be more time efficient given present levels of processing technology, mainly due to the longer processing time required for ARD recordings. However higher numbers of people were required for observer counts, which may be problematic when there is a shortage of appropriately skilled observers at the required time of year.
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.