Forty breeding colonies of three petrel species were found on 35 of 71 islands surveyed in southern Fiordland, Fiordland National Park, New Zealand, in November and December 2017. Almost all islands in Chalky Inlet, Preservation Inlet, Cunaris Sound, Long Sound, and Isthmus Sound were surveyed. Sooty shearwater (Ardenna grisea) was the most widespread and abundant species, with an estimated 23,425 burrows on 25 islands. Broad-billed prions (Pachyptila vittata) were breeding on nine islands (9,940 burrows estimated), and mottled petrels (Pterodroma inexpectata) on five islands (1,240 burrows estimated). This is a 3-fold increase in the number of petrel colonies in Chalky and Preservation Inlets and associated waterways identified in published accounts, and the first estimate of the number of burrows on each island. Long-term survival of most of these colonies is dependent on ongoing control of stoats (Mustela erminea) on islands in these southern fjords. The persistence of remnant petrel colonies on small islands is probably due to stoats being infrequent invaders that are unable to persist when migratory petrels depart at the end of the breeding season.
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.
Variable oystercatcher chicks (Haematopus unicolor) were banded at the Kaikōura Peninsula between summer 1999–2000 and summer 2016–2017. Prior to colour banding, there were no reports of Kaikōura Peninsula oystercatchers being sighted at other locations. Since summer 2006–2007 colour banding sequences have been available and these unique identifiers enabled movements of individual juvenile and immature birds to be determined. Forty-two colour banded chicks fledged, and 25 of these have been sighted at 11 locations between Collingwood 215 km to the northwest, and the Avon-Heathcote Estuary near Christchurch, 145 km south. Twelve of the 25 birds sighted away have not been seen back at the Kaikōura Peninsula, the other 13 returned of which 4 travelled away for a second time and did not return. Seventeen birds were not seen away from the Kaikōura Peninsula but 7 with no sightings for periods over 7 months may been away and returned. Siblings often went to different locations. Of 9 pairs of same nest siblings, 1 pair stayed at the Kaikōura Peninsula, 1 pair went initially to Nelson and 1 pair to the Avon-Heathcote Estuary, and birds of the other 6 pairs went to different locations including staying at Kaikōura. Birds seen at Nelson were also seen at the Avon-Heathcote Estuary.
Variability of face and wing pattern and of leg and bill colour, and differences in bill and wing lengths, were assessed in Anas superciliosa (Anatidae) specimens from Pacific Islands, Australia, and New Zealand regional populations. The same 3 broad face patterns and 4 wing patterns were found in all populations. Frequency distributions of face patterns, but not wing patterns, differed significantly between populations. The most common face pattern in Australia was very rare in New Zealand and uncommon in Pacific Islands. A secondary face pattern in Pacific Islands and New Zealand was absent in Australia. Australian and New Zealand ducks did not share bill colour and pattern and no legs of New Zealand birds displayed yellow/orange hues common to 35% of Australian specimens. Bill and wing lengths of Pacific Islands specimens were significantly shorter than all others while wing lengths of male specimens from northern Australia were significantly shorter than those from southern Australia and New Zealand. These differences offer emphatic support for historic subspecific differentiation of Pacific Island specimens. Historic, but now discarded, taxonomic distinction between Australian and New Zealand populations based on phenotype could be reconsidered.
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”).
A national survey of breeding red-billed gulls (Larus novaehollandiae scopulinus) was carried out during 2014–2016 to establish the present status of the species. Observers were asked to find and report all breeding colonies, starting with a check of previously reported breeding sites. Standardised means of conducting these surveys were developed, publicised, and largely applied. Around 27,831 pairs of red-billed gulls were recorded nesting in New Zealand during the survey: 14,713 pairs at 122 South Island sites; 12,676 pairs at 124 North Island sites; and 442 pairs at 14 sites on the Chatham Islands. Other than colonies on the Three Kings Islands (1,763 pairs) and Takapourewa/Stephens Island (1,250 pairs) there were no large concentrations on offshore islands. The largest mainland concentrations were at Kaikoura (3,210 pairs), Taiaroa Head (2,145), Rotorua (2,277) and Marsden Point (1,190). Although the accuracy of previous estimates is questionable, the red-billed gull nevertheless appears to have declined nationally since the mid-1960s. Possible reasons for the decline are discussed and a proposal for future monitoring of the species is proposed.
In September 2002 and 2014 respectively, 2,077 and 1,704 prospecting Hutton’s shearwaters were colourmarked on the ventral plumage at their breeding grounds at Kōwhai River, Seaward Kaikōura Ranges, New Zealand. Large numbers (425,516 in 2002, and 106,900 in 2014) of marked and unmarked birds were then counted from small boats off the Kaikōura coast between Haumuri Bluff and Ohau Point. A hypergeometric sampling model was fitted these counts, leading to population estimates of N = 459,290 (95% CI = 434,306-484,733) birds in 2002 and N = 590,407 (95% CI = 543,992–642,697) individuals in 2014. These estimates include both breeding and non-breeding birds and indicate that between 2002 and 2014 the population trend was about +2% per year.
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.