Of 4 importations of Canada goose Branta canadensis into New Zealand, 2 (in 1905, 1920) resulted in breeding. Commencing in 1907, multiple and repeated releases of the 1905 geese and their progeny had, by 1922, established flocks of several hundred distributed along the eastern Canterbury and Otago foothills of the Southern Alps. Thereafter, the geese spread widely but remained resident and breeding only in the South Island. Establishment of Canada geese in North Island commenced in 1969 with the first of 4 transfers by the Wildlife Service, collectively totalling 280 birds from Canterbury’s Lakes Ellesmere and Forsyth, to coastal Wairoa lakes and nearby locations. The Wildlife Service assisted numerous other transfer and release initiatives, of at least 800 birds, in North Island in the 1970s and 1980s, principally by Wellington and Auckland Acclimatisation Societies, Ducks Unlimited, and private waterfowl enthusiasts. At the same time it supported transfers of 450 geese to the South Island’s West Coast. From these multiple releases Canada geese have become widespread in rural New Zealand.
Kiwi (Apteryx spp.) are the most vocal of the ratites. Of the 5 Apteryx species only 2 have previously been subject to detailed vocal analysis: the North Island brown kiwi (A. mantelli) and the little spotted kiwi (A. owenii). This paper describes the vocalisations of the great spotted kiwi (A. haastii), the largest of the Apteryx species. Acoustic recorders were installed near the breeding den sites of 7 great spotted kiwi pairs residing in Hawdon Valley, Canterbury between November 2012 and March 2013. A total of 133 whistle vocalisations from 10 individuals were subject to detailed temporal and spectral analysis. Male and female syllables were found to be sexually dimorphic; syllables in male calls tended to be longer and more highly pitched than their female counterparts. Despite this dimorphism, patterns of intra-call variation were consistent between the sexes. It appears that intra-call variation is a trait which varies markedly within the Apteryx genus.
Prior to 1992 the total population of New Zealand king shag (Leucocarbo carunculatus) was estimated to be about 300 individuals. Between 1992 and 2002, colonies in the outer Marlborough Sounds, New Zealand were surveyed by boat and the total population was estimated to be 645 birds. About 92% of all birds occurred at Duffers Reef, North Trio Island, Sentinel Rock, and White Rocks, with an estimated 102-126 breeding pairs. A survey in February 2015 was the first to be conducted from the air. All colonies were photographed within 44 minutes prior to the morning departure and the total population was estimated to be 839 individuals. A total of 187 pairs/nests were recorded using aerial 3D images of all breeding colonies in June 2015. North Trio Island was the largest breeding colony with 33.7% of all nests, followed by Duffers Reef with 18.7% of all nests. Despite the larger revised population size, the species remains Nationally Endangered.
The white-flippered penguin (Eudyptula minor albosignata) population on Banks Peninsula, New Zealand, was extensively preyed on by mammalian predators during the 1980s and 1990s with the loss of many colonies and the reduction in size of others. This paper presents the results of a 20-year study designed to identify the predators primarily responsible for these losses. It was based on the monitoring of 9 colonies ranging in size from 2 to 37 nests on a 1.7 km section of rocky coastline. Predators were trapped in the largest colony to determine the species present and their relevant behaviour. The other colonies were left unprotected, 6 of which were accessible to predators and 2 were not. Predation of penguins was first observed in the area in 1981 and it occurred annually through to the end of the study in 1995. Five of the 6 unprotected colonies were lost in 1982 and 1983 while the inaccessible colonies were unaffected. The remains of penguins that had been preyed on were found in the ‘protected’ colony in 11 of the 15 years between 1981 and 1995. These had been taken during the second half of the moulting season in February, and during the non-breeding season from April to August. No predation was observed during September to January when the penguins were breeding. A total of 47 mustelids were trapped in the ‘protected’ colony of which 43 (91%) were ferrets (Mustela furo). Overall there were 16 instances of predation that could be attributed to ferrets and 1 that was attributed to a ferret although the predator was not caught. The onset and sustained period of penguin predation by ferrets followed an eruption in their numbers Banks Peninsula-wide. This was most likely triggered by a corresponding increase in the numbers of rabbits (Oryctolagus c. cuniculus), their primary prey.
The southern black-backed gull (Larus dominicanus) is a common species throughout New Zealand, and has a significant presence in Auckland City. Large colonies are present on Rangitoto Island only 8 km from the city’s centre. The proximity of these colonies to the anthropogenic resources of the city may have influenced breeding locations and local populations. Using field data from the 2012/13 breeding period, we compare the current status of the breeding population on Rangitoto Island with historical data collated from literature. The Rangitoto population exhibited rapid growth throughout the early 20th century, a pattern attributed to environmental changes associated with European settlement and development. Since the 1980s, the colony sizes have declined, a change that is consistent with other gull populations both nationally and globally. The driver of the population changes is likely to be the availability of food and the expansion of vegetation into the colonies. Human disturbance and predation are discounted as impacting on population change.
Cyanobacterial blooms in Lake Rotoiti have been linked to nutrient flows from Lake Rotorua via the Ohau Channel. To mitigate this, a diversion wall was constructed in 2008 that was designed to redirect water entering Lake Rotoiti from Lake Rotorua into the Kaituna River. One concern was whether the presence of the diversion wall might have adverse impacts on the abundance of birds using the lake. Monthly bird counts were undertaken at 8 sites in Lake Rotoiti, over 8 years, and which spanned the period before, during and after construction of the wall. Generalised linear mixed effect models and AIC were used to investigate any effects of the wall on 6 bird species. There was no apparent impact of the wall on 5 of the species. The sixth species, little black shag (Phalacrocorax melanoleucos), was more abundant in sites surrounding the wall post-construction, and appeared to be using the wall for roosting and to hunt for smelt.
The distribution, status and trends of grey-faced petrel (Pterodroma macroptera gouldi) populations are summarised from historical records from as early as the 1800’s, but predominantly over a 40 year period from the 1970’s and 1980’s to the present day. We tallied the most recent of 104 island population estimates to give a total range of 72,398-286,268 burrows over a minimum area of 37,967 ha. On predator-free islands (n = 9) during winter, the mean burrow occupancy rate was 60% (± 18 % SD). Fewer than 1000 burrows were detected from 20 mainland sites over an unspecified area. Implications for the conservation of this species are discussed.
Bird counts were carried out in Zealandia sanctuary, Wellington, New Zealand, along a 6.3 km slow-walk transect, every 3 weeks for 4 years (2011-2015). The mean ± se number of species detected per count was 30.0 ± 0.4 (range 22-37) and the mean ± se total of individuals detected per count was 572.7 ± 12.8 birds (range 361-809). Of 43 species detected, 15 occurred on every count, 8 on most, 13 less frequently and 7 only occasionally. Forest birds were mostly first detected by sound, but water or wetland birds mostly by sight. For 35 species with sufficient data to model, significant seasonal changes occurred in 9 species (26%) and significant annual changes in 4 species (11%), with the total of birds counted peaking in late summer/autumn. Song output varied amongst passerines, with large seasonal effects in 6 European introduced species, but lower seasonal effects in 9 native species.