Australasian little grebe (Tachybaptus novaehollandiae) was detected at the Whangarei sewerage wetlands at Kioreroa Road, in September–October 1996, and since 2012 has attempted to breed. Between October 2015 and April 2017, a pair of grebes produced 4 fledglings from 5 nesting attempts. Adults fed chicks for 26–29 days by diving in open areas with swamp lily (Ottelia avalifolia). Fledglings began independent foraging between 19 and 26 days old. Fledglings were not seen at the site after reaching c. 55-days old. The young from late clutches left the natal site in March–April, 3 weeks after their parents were last detected there. The site was not used by any grebes in June and July.
Face, wing, bill, and leg characteristics of grey ducks (Anas. s. superciliosa), of captive-raised F1 and backcrossed grey duck x mallard (A. platyrhynchos) hybrids, and of wild “grey-like” and “mallard-like” ducks in New Zealand were evaluated to assist recognition of grey duck x mallard hybrids in the field. Face pattern was the single character best able to discriminate grey ducks from all others, most grey-like hybrids from all mallard-like hybrids, but not most F1 and backcrossed mallard hybrids from mallards. Upper wing pattern, and bill and leg colours assisted discrimination alongside face pattern but not so on their own. The extensive phenotypic variability now apparent within the combined grey duck – mallard population in New Zealand restricts consistent discrimination to 3 “taxa”: grey ducks, grey-like ducks (“grallard/greylard”), and mallard-like ducks (“New Zealand mallard”).
Data on the effects of aerial 1080 operations on non-target bird species in New Zealand are scarce and largely limited to short-term colour-banding or radio-tracking studies, or standardised call counts. During a 22-year study in Tongariro Forest, all 142 radio-tagged North Island brown kiwi (Apteryx mantelli) survived 4 landscape-scale (20,000 ha) aerial broadcast 1080 operations targeting brush-tailed possum (Trichosurus vulpecula) and rats (Rattus spp.). Furthermore, both kiwi chick survival to 6 months old and New Zealand fantail (Rhipidura fuliginosa) nesting success were significantly higher in the first 2 breeding seasons following the use of 1080 poison than in subsequent years of the 5-year cycle. We observed several episodes of ferret (Mustela furo) killing multiple adult kiwi, particularly in the last half of the 1080 cycle. Population modelling showed that a 5-year 1080 operation cycle resulted in population gains for 2 years, followed by declines in the remaining 3 years that largely negated these benefits. Our data thus support the shift to a 3-year 1080 operation cycle which will more likely result in this kiwi population growing at close to the 2% per year target set by the 2018–2028 Kiwi Recovery Plan.
An observational study on the diet and breeding success of morepork (ruru; Ninox novaeseelandiae) was undertaken using video capture methods during the 2016-2017 breeding season on Tiritiri Matangi Island. The study investigated diet composition, frequency of prey deliveries, timing and frequency of chick provisioning, the behaviour of morepork and their young at 10 nest sites, and considered the possibility that morepork predation was having a negative impact on species of conservation importance. Tree wētā (Hemideina spp.) were found to be the most common prey type consumed at nest sites. Evidence of predation of bird species of conservation importance including stitchbird (hihi; Notiomystis cincta) was also found. Prey species continue to exhibit positive population growth rates, indicating predation rates are too low to have a significant destabilizing effect. However, as the population of moreporks has also grown, it is recommended that their impact on prey species be monitored.
Between 2002 and 2011, Buller’s albatrosses (Thalassarche bulleri bulleri and T. b. platei) accounted for 34% of albatross interactions in New Zealand trawl fisheries. However, the relative impact of commercial fisheries on each taxon is uncertain as identifying individuals by morphology is challenging. The aim of this research was to develop a genetic identification method for the 2 taxa. To this end, DNA was isolated from blood samples collected from a total of 73 birds breeding at northern Buller’s albatross colonies on the islets of Motuhara and Rangitatahi (total n = 26) and southern Buller’s albatross colonies located on Solander Island and North East Island (total n = 47). The degree of genetic differentiation between northern and southern Buller’s was estimated by using DNA sequences from a 221 bp segment of the mitochondrial Control Region. The genetic structure between northern and southern groups was high (pairwise ΦST = 0.621, P < 0.001). A Bayesian assignment method was used to determine provenance of individuals randomly sampled from fisheries bycatch (n = 97). All bycatch individuals were assigned with maximum probability to either the northern (n = 19) or southern taxon (n = 78; P = 1.00). This study demonstrated that sequences from the mitochondrial control region could reliably be used to assign individuals to either northern, or southern breeding populations, and can be used for determining the provenance of seabird bycatch.
Observer call count surveys are utilised throughout New Zealand to monitor kiwi populations. The development of affordable autonomous acoustic recorders by the Department of Conservation has enabled the collection of large quantities of digital data. Utilising call count data from the North Island brown kiwi (Apteryx mantelli) monitoring programme at Whenuakite from the 2010 and 2015 survey periods, a retrospective comparison between data collected by human observers and acoustic recorders was undertaken. Both survey methods indicated an increase in the number of kiwi calls per hour between the 2010 and 2015 surveys. The overall ratio of the number of calls per hour detected by acoustic recorders to those detected by human observers was 1:1.52. Results from the occupancy modelling indicated that the average detection probability for human observers was almost twice as high as that for acoustic recorders. Furthermore, increasing the number of sites for monitoring kiwi populations improved the associated level of precision of the derived occupancy probability estimates. Adjusting the survey design to the underlying characteristics of the kiwi population are therefore important to gain reliable estimates of their population trajectory.
Zealandia (Karori Sanctuary) is a forest sanctuary which is surrounded by a predator-exclusion fence, and is situated in the Wellington city town belt, New Zealand. Following eradication of introduced mammals from within the fence in 1999, 10 species of endemic forest birds were reintroduced between 2000 and 2011, and 2 other species recolonised naturally. Five-minute bird counts were used to assess changes in the Zealandia diurnal forest bird community over 2 time periods: 1995-98 to 2002-05, and 2002-05 to 2013-16, as well as changes over the full 21 year period. Tui (Prosthemadera novaeseelandiae) was the only bird species present before the fence was completed that showed a significant, year-round positive response to mammal removal. Following the recreation of a diverse and abundant endemic bird community post-2005, detection rates for most of the species that were present before 1999 declined significantly. This included highly significant declines in detection rates for 3 native bird species: silvereye (Zosterops lateralis), grey warbler (Gerygone igata) and New Zealand fantail (Rhipidura fuliginosa). These results suggest that populations of the most common and widespread native and introduced birds are only weakly limited by mammalian predation, but can be rapidly outcompeted by restored endemic bird species if predators are removed. The forest bird community in Zealandia is now more similar to that on nearby Kapiti Island (the source site for many of the bird species translocated to Zealandia) than it is to the bird community that existed at the site before the fence was built.
This paper summarises the variations in breeding periodicity in the Australasian – South Pacific region, including recent evidence contrary to previous knowledge. Birds shown to breed in the Samoan islands throughout the year are white-tailed tropicbird (Phäethon lepturus), white-rumped swiftlet (Aerodramus spodiopygius), buff-banded rail (Gallirallus philippensis), brown noddy (Anous stolidus), white tern (Gygis alba) and wattled honeyeater (Foulchaio carunculata). In addition, crimson-crowned fruit-dove (Ptilinopus porphyraceus), blue noddy (Procelsterna caerulea), cardinal honeyeater (Myzomela cardinalis) and Polynesian triller (Lalage maculosa) breed in at least 9 months of the year. The Samoan whistler (Pachycephala flavifrons) has been found breeding in 8 months and the Samoan starling (Aplornis atrifusca) in 7 months of the year.
Over 11 years, the presence of bird species detected within a garden in Kaikōura, New Zealand, were recorded on a weekly basis. Of the 19 species, Eurasian blackbird (Turdus merula merula), house sparrow (Passer domesticus domesticus) and common starling (Sturnus vulgaris vulgaris) were most commonly detected followed by silvereye (Zosterops lateralis), the most commonly detected native bird. New Zealand falcon (Falco novaeseelandiae), Australian magpie (Gymnorhina tibicen) and California quail (Callipepla californica brunnescens) were each seen once. Others recorded were bellbird (Anthornis melanura melanura), chaffinch (Fringilla coelebs), common redpoll (Carduelis flammea), dunnock (Prunella modularis), European goldfinch (Carduelis carduelis britannica), European greenfinch (Carduelis chloris), grey warbler (Gerygone igata), red-billed gull (Larus novaehollandiae scopulinus), song thrush (Turdus philomelos), South Island fantail (Rhipidura fuliginosa fuliginosa), yellowhammer (Emberiza citrinella) and welcome swallow (Hirundo neoxena neoxena). Ten species exhibited significant seasonal variation; 4 showed significant increases and 2 decreases over the 11 years of the study. This study has shown that simple presence/absence observations of a species on a weekly basis can provide an index of numbers, and demonstrate seasonal movements and medium-term changes of bird species within an urban garden.