A ground survey of Fiordland crested penguins (tawaki; Eudyptes pachyrhynchus), breeding between Lee Bay and White Rock Point, northeast Stewart Island was carried out from 1–6 September 2019, to obtain a population estimate for the area. A total of 128 nests was found along the ~40 km of coast, 107 of which were located in caves on the cliffy shoreline rather than in the forest as is typical of South Westland breeding areas. Access along this coast is often difficult; however, the confinement of most nests to caves allows for a more accurate search than in forest colonies such as those in South Westland and Milford Sound. The results of this survey suggest that a significant breeding population is present on mainland Stewart Island and needs to be considered in future management plans for the species. Additional surveys of the remaining ~700 km of coastline should be conducted to obtain a better estimate of the entire population.
Nesting outcomes of Canada geese (Branta canadensis maxima) in Canterbury, New Zealand were recorded from a sedentary population nesting at coastal Lake Forsyth (1967–70) and from a seasonally migratory population nesting in headwater valleys of the Waimakariri River (1966–80). Mean clutch size in 462 Lake Forsyth nests was 5.3 (sd = 1.3) eggs, with clutches of 4, 5, and 6 eggs comprising 17%, 30% and 30% respectively of the total. Goslings hatched from 67.4% of 1,602 eggs in 298 monitored nests, and the entire clutch hatched successfully in 42.6% of the monitored nests. Mean productivity at hatching was 3.6 (sd = 2.3) goslings per nest. Mean clutch size in 1,211 Waimakariri River headwaters nests was 4.5 (sd = 1.3), with clutches of 4, 5, and 6 eggs comprising 25%, 32%, and 20% respectively of the total. Goslings hatched from 63.3% of 3,952 eggs in 871 monitored nests, and the entire clutch hatched successfully in 30.5% of the monitored nests. Mean productivity at hatching was 2.9 (sd = 1.9) goslings per nest. Relative to Canada geese in their native North American range, geese nesting at Lake Forsyth laid clutches of similar size, had similar hatching success but higher nest success whereas geese nesting in the Waimakariri River headwaters laid, on average, conspicuously smaller clutches, had similar hatching success, but higher nest success.
New Zealand scaup (Aythya novaeseelandiae) counts are collated from a total of 12,145 site visits nationally between 1888 and 2018 to estimate their distribution, population status, and trends. Based on systematic counts of large flocks on lakes between 1984–2018, there are about 11,000 New Zealand scaup nationally. This estimate must be interpreted with caution, as if birds are highly mobile the risk of overestimating the population is high. The distribution of New Zealand scaup strongholds (>50 adults) is compared to historical descriptions and trends in water quality. As lakes become more eutrophic over time, the birds move and the population declines. Research should focus on aerial vs ground counts, telemetry/satellite and/or banding studies of bird movement, gender, diet, predation, and littoral zone quantity and quality (
Abstract: The Floreana mockingbird (Mimus trifasciatus) is one of the most endangered passerines in the world, with a global population of c. 400 individuals, restricted to two isolated islets: Champion and Gardner-by-Floreana. Due to its rarity and the inaccessibility to these islets, the biology of the Floreana mockingbird has remained poorly documented. Here we present a study on the diversity of food items consumed by Floreana mockingbirds prior to the rainy season. We recorded 269 foraging bouts, from 148 individuals on three independent sampling events. Floreana mockingbirds exhibited a generalist diet, which included flowers, nectar, stamens, sap, fruits, seeds, and seedlings from 12 plant species; larvae, pupae and adults of at least 10 arthropod orders; and small vertebrate prey, carrion, and egg contents. The diversity of food items between months and islets supports the idea of a generalist diet for the species. Our study provides useful information to identify and monitor the abundance of key resources for the species as part of the restoration of Floreana Island.
Understanding how animal behaviours are affected by external factors such as time of day/year and weather conditions is fundamental to understanding the basic biology of a species and can thus help with conservation management. Weka (Gallirallus australis) is typically crepuscular in its habits, but there is some evidence to suggest that it can also be nocturnal. We conducted a longitudinal study of the nocturnal habits of the western weka (G. australis australis) located at Manaroa in New Zealand’s Marlborough Sounds. We used model selection information criterion to examine how the numbers of weka in an open environment (lawn) changed with time of night and season, as well as differing weather and moonlight conditions. In addition, we undertook night-time behavioural observations during a four-month subset of the study period. Numbers of weka declined through the night and increased non-linearly around dawn. Weka were more likely to be present during moonlit nights and at warmer temperatures during the evening. There was considerable seasonal variation, with the highest number of weka during autumn and lowest during summer. Behavioural observations demonstrated that weka were active throughout the night, with foraging being the most frequently-observed behaviour.
Public and our observations during 1999–2004 suggested that tūī (Prosthemadera novaeseelandiae) visited the city of Hamilton during March to October only, outside the nesting season. From 2004 onwards, we captured and banded 51 adult tūī and fitted radio transmitters to 41 in Waikato urban areas to locate nests. We directly observed 15 nests to determine nesting success and gather evidence of any predation events. Tūī moved 5–23 km from urban areas to surrounding native forests at the onset of nesting, but only four (29%) of 14 unmanaged nests fledged young, due mostly to predation by ship rats (Rattus rattus), swamp harriers (Circus approximans), and brushtail possums (Trichosurus vulpecula). Subsequent effective pest mammal control in forests around Hamilton was associated with greatly increased year-round tūī abundance and nesting in Hamilton. These results confirm previous findings that tūī move widely in winter; that they readily cross pasture in the absence of forest corridors, and that they will permanently inhabit urban areas. Provided adequate food is available, effective control of ship rats and possums can rapidly (1–4 years) increase tūī visits and nesting within 20 km of managed sites, enabling recolonisation of proximate urban habitats by this iconic endemic taxon, despite previous evidence for natal philopatry.
Abstract: We report Records Appraisal Committee (RAC) decisions regarding Unusual Bird Reports received between 1 January 2019 and 31 December 2020. Among the 149 submissions accepted by the RAC were the first New Zealand records of collared petrel (Pterodroma brevipes), South Polar skua (Catharacta maccormicki), and rose-crowned fruit dove (Ptilinopus regina). We also report the first accepted breeding record for gull-billed tern (Gelochelidon nilotica), and the sec- ond accepted sightings of Australian white-faced storm petrel (Pelagodroma marina dulciae) and buff-breasted sandpiper (Tryngites subruficollis). Other notable records included the first records of Atlantic yellow-nosed mollymawk (Thalassarche chlororhynchos) from the Snares Islands, nankeen kestrel (Falco cenchroides) from Antipodes Island, long-tailed skua (Stercorarius longicaudus) from the Chatham Islands, and Arctic tern (Sterna paradisaea) from the Bounty Islands.
More than 3,500 Holocene bones, representing at least 853 individual birds, have been recovered on the uninhabited subantarctic Auckland Islands, south of New Zealand. Today this island group has a rich seabird and land-bird fauna, although there have been at least four bird extinctions (a duck, two petrels and a plover) due to predation by introduced mammals and hunting by humans. The Holocene bone fauna, overwhelmingly from sand dunes on Enderby Island, is dominated by seabirds still found at the island group (particularly diving petrels Pelecanoides spp., southern royal albatrosses Diomedea epomophora, and prions Pachyptila spp.). Remains of all endemic taxa (apart from the Auckland Island tomtit Petroica macrocephala marrineri) were recovered from the deposits. All the taxa known to have gone extinct at the island group have now been recovered in Holocene bone deposits, except for the shore plover (Thinornis novaeseelandiae). The deposits indicate also that the abundance of other species has changed. For example, both the eastern rockhopper penguin (Eudyptes filholi) and white-chinned petrel (Procellaria aequinoctialis) are common in the Enderby Island deposits but are rare on the island today, and the Auckland Island rail (Lewinia muelleri) is present as bones in these dunes but has no historical records from the island. This information on the prehistoric distributions of birds will assist the management of the avifauna of the Auckland Islands, which is currently the subject of a major ecological restoration programme.
Since the European discovery of the Auckland Islands, at least ten species of land mammals have been introduced there. Most arrived in the first half of the ninteenth century during periods of exploitation by sealers and whalers, followed by short-lived Māori and European settlements at Port Ross. Several species required multiple introductions before becoming established. For those populations that naturalised, cattle (Bos taurus) occupied Enderby Island and were eradicated by 1993, goats (Capra aegagrus hircus) remained restricted to the northern end of Auckland Island and were eradicated by 1991, while pigs (Sus scrofa) spread across the entire Auckland Island and remain there today. Rabbits (Oryctolagus cuniculus) established on Rose and Enderby Islands, and were eradicated in 1993. Cats (Felis catus) and mice (Mus musculus domesticus) were both first recorded in 1840 on Auckland Island and remain there today. Rats (Rattus spp.) have never established on the Auckland Islands. Collectively, cattle, goats, sheep (Ovis aries), pigs, and rabbits transformed habitats and altered ecosystem processes, and suppressed tussock, megaherbs, and woody vegetation on Auckland, Enderby, Rose, Ewing, and Ocean Islands. Cats and pigs are together responsible for the extirpation or major reduction of surface-nesting and burrowing seabird colonies, and ground-nesting land birds from Auckland Island. Before dying out on Enderby Island, pigs had similar impacts there. Mice have altered invertebrate community composition and are likely responsible for lower abundancies of wētā (Dendroplectron aucklandense) and large weevils (Curculionidae) on Auckland Island. Disappointment Island remained free of introduced mammals, while on Adams Island they had only fleeting and minimal impact. Humans also had direct impacts on birds through hunting for consumption, with large surface-nesting seabirds severely affected around Port Ross. The Auckland Island merganser (Mergus australis) was driven to extinction by presumed mammal predation and well-documented museum collecting. Eradication of pigs, cats, and mice from Auckland Island and Masked Island (Carnley Harbour) would remove the last introduced mammals from the New Zealand subantarctic region.