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.
We report Records Appraisal Committee (RAC) decisions regarding Unusual Bird Reports received between 1 January 2013 and 31 December 2014. Among the 126 submissions accepted by the RAC were the 1st New Zealand records of buff-breasted sandpiper (Tringites subruficollis) and dusky woodswallow (Artamus cyanopterus), the 2nd accepted record of American golden plover (Pluvialis dominicus), and the 3rd accepted record of Franklin’s gull (Larus pipixcan). Other notable records included a breeding record of white-winged black tern (Chlidonias leucopterus) from Marlborough, the 1st accepted records of little black shag (Phalacrocorax sulcirostris) from Stewart Island and the Snares Islands, the 1st accepted records of nankeen night heron (Nycticorax caledonicus) and Australian coot (Fulica atra) from the Snares Islands, and the 1st accepted record of eastern curlew (Numenius madagascariensis) from Campbell Island. In addition, notable influxes of Pacific heron (Ardea pacifica), little egret (Egretta garzetta), glossy ibis (Plegadis falcinellus) and white-winged black tern occurred during 2013-14. The RAC also reconsidered New Zealand’s only previously accepted sighting of black falcon (Falco subniger, reported from Gisborne in 1983), and determined that the record can no longer be accepted and that this species should be removed from the New Zealand list.
The hihi (Notiomystis cincta) is a small threatened passerine endemic to New Zealand, for which few methods are known for ageing and sexing wild unbanded individuals. We monitored hihi on Tiritiri Matangi Island over 3 years, studying moult and other sexing and ageing techniques. Juvenile hihi before their first partial moult can be sexed by the white bases of primary coverts on males, which appear brown in females. After juveniles undergo their first partial moult, they appear similar to adults; however juvenile males retain old feathers in their primary coverts, alulae, or sometimes greater coverts or inner primaries, while adults undergo a complete moult. These patterns can be difficult to see in juvenile females, but wear of juvenile tails is much greater than in adults at any given time of year, making ageing of females reliable. Moult in the outer primaries and secondaries in autumn also indicate adult birds. This information should help inform future translocations and attempts to monitor viability of wild populations. Finally, we also comment on alternative definitions for ageing criteria from Melville (2011), based not on suspected birth-dates, but on appearance of plumage in hand.
The foraging ecology of Pitt Island shag (Stictocarbo featherstoni) was studied using GPS archival and Time Depth Recorder devices deployed on incubating birds. Pitt Island shags foraged exclusively during daylight, with a tendency for males to forage mainly during mid-morning and late afternoon, and females in the early morning and around mid-day. Mean foraging distance from colonies was 5.2 km (range 0.4-18.2 km), with males (mean 9.7 km) foraging significantly further than females (3.7 km). Both sexes showed high foraging site fidelity. The depth of most (83%) dives > 5 m deep were similar to the depth of the preceding dive (within 30%), indicating that birds are almost exclusively benthic feeding with the small fluctuations in dive depth likely reflecting changes in seafloor topography. Mean dive depth was 6.6 m, with maximum depth 24.4 m, although 90% of all dives were shallower than 13 m deep. Mean dive duration was 22 s, with a maximum of 69 s, although over 90% of dives were shorter than 40 s. There was a positive relationship between dive duration and dive depth, where deeper dives had longer duration. Mean rest period was 19 s with a weak positive relationship between rest period and duration of the preceding dive. Mean percentage time underwater during each foraging trip was 50.1%, indicating relatively high foraging efficiency. Favoured foraging locations in shallow inshore waters is likely to be a response by birds selectively foraging in sheltered waters protected from oceanic swells. This may be a factor influencing population declines as it intensifies risk to birds as potential threats may be more concentrated in these areas.
Hutton’s shearwater (Puffinus huttoni) currently breeds only in 2 colonies in the Seaward Kaikoura mountains, South Island, New Zealand. Conservation measures now include re-locating young to establish a new low altitude colony. To assess the genetic similarity of birds breeding in the 2 colonies as a basis for decisions on sourcing recruits to the present and potentially other new colonies, we genotyped 9 microsatellite loci, with 3-13 alleles, in 30 birds from the Kowhai River catchment colony and 29 from Shearwater Stream. There was no significant population genetic differentiation between the 2 sampling locations. Our results suggest that there would be little genetic risk to mixing birds from both relict colonies in newly established colonies. Future analyses of the former distributions of Hutton’s shearwater, the fluttering shearwater (P. gavia), and the extinct Scarlett’s shearwater (P. spelaeus) will require an analysis of the levels of genetic similarity between birds from the relict colonies and those of former, widely separated colonies.
Alofi, Futuna and Uvea (also called Wallis), 3 islands situated north of Fiji and Tonga archipelagos, are rarely visited by ornithologists. We present new data on the avifauna obtained during surveys in 2014 and we compare them with previous surveys made in the 1920s, 1980s and 1990s. We recorded the extirpation of 1 species (friendly ground-dove, Alopecoenas stairi) probably related to predation, and the decline of another (lesser shrikebill, Clytorhynchus vitiensis) linked to deforestation. Although the recent arrival of the black rat (Rattus rattus) in Futuna is a potential threat for the blue-crowned lorikeet (Vini australis), no decline is apparent at the present time. In general, most landbirds seemed common despite loss of native habitats and hunting pressure; similarly, the seabird populations and number of species appeared stable, a situation probably linked with the general decrease of harvesting. Finally, 2 breeding species (spotless crake, Zapornia tabuensis, and tropical shearwater, Puffinus bailloni) and 3 vagrants (white-faced heron, Egretta novaehollandiae, masked lapwing, Vanellus miles, and pectoral sandpiper, Calidris melanotos) are added to the list.
The remnant wild populations of the critically endangered orange-fronted kākāriki (Cyanoramphus malherbi) are restricted to 3 North Canterbury valleys where they co-occur with the yellow-crowned kākāriki (C. auriceps). Mixed pairs of Cyanoramphus kākāriki species have been documented throughout the genus, but the extent to which orange-fronted and yellow-crowned kākāriki mate assortatively, particularly when one species outnumbers the other, remains unclear. Here, we investigate the level of assortative mating between orange-fronted and yellow-crowned kākāriki. Based on 355 confirmed nests during 1999-2011, 99% (n = 351) were pure pairings and 1% (n = 4) were mixed pairings. With one exception, the ratio of orange-fronted to yellow-crowned kākāriki encountered during annual surveys ranged between zero and 0.78. These results indicate that the 2 congeners exhibit assortative mating, even when the orange-fronted kākāriki is outnumbered by yellow-crowned kākāriki. The low levels of mixed pairing we observed suggests that the reintroduction of orange-fronted kākāriki should not be precluded to sites where yellow-crowned kākāriki already occur.
Monitoring of wetland birds was undertaken at Lake Ellesmere/Te Waihora during the post-breeding period in February 2006, 2007 & 2008. Census totals were 38,726, 39,917 and 39,175 individual birds over the 3 years, respectively, and 46 wetland bird species were recorded. Nine species had a maximum count exceeding 1000 individuals, including 11,245 grey teal (Anas gracilis), 10,651 black swan (Cygnus atratus), 5776 pied stilt (Himantopus himantopus), 4899 Canada goose (Branta canadensis), 3405 Australasian shoveler (Anas rhynchotis), 1873 banded dotterel (Charadrius bicinctus), 1640 paradise shelduck (Tadorna variegata), 1592 black-billed gull (Larus bulleri) and 1389 mallard/grey duck (A. platyrhynchus/A. superciliosa). Fourteen species were recorded in numbers that met or exceeded the 1% Ramsar international significance criterion: Australasian crested grebe (Podiceps cristatus), black cormorant (Phalacrocorax carbo), white heron (Ardea modesta), black swan, paradise shelduck, grey teal, Australasian shoveler, pied stilt, black stilt (Himantopus novaezelandiae), banded dotterel, wrybill (Anarhynchus frontalis), black-billed gull, black-fronted tern (Childonias albostriatus), and Caspian tern (Hydroprogne caspia). Lake Ellesmere also supported populations of migratory bird species that are uncommon in New Zealand including curlew sandpiper (Calidris ferruginea), sharp-tailed sandpiper (C. acuminata), red-necked stint (C. rufficolis), Pacific golden plover (Pluvailis fulva) and white-winged black tern (Childonias leucopterus). When compared to other coastal wetlands in terms of bird numbers, Lake Ellesmere ranked as the most important site in the Canterbury Region.
We used data from 3 sources to examine the population size and trend of Salvin’s albatrosses (Thalassarche salvini) breeding on Proclamation Island, Bounty Islands, New Zealand. Island-wide counts of breeding birds during incubation resulted in totals that declined 14%, from 3065 in 1997 to 2634 in 2004. A count of breeding albatrosses over part of the island in 2011 indicated a further decline of 13% between 2004 and 2011, and an overall decline of 30% between 1997 and 2011. Additional counts on part of Depot Island indicated a decline of 10% in the numbers of breeding pairs between 2004 and 2011. Daily observations of 70 nests showed that hatching spanned the period from 5 to 21 November 1997, with a median of 15 November, apart from 5 eggs that had not yet hatched by the end of the study period. Based on the banding and recapture of chicks banded in March 1985 annual survival was estimated at 0.926. The scale of the decline estimated in this population has resulted in the conservation status of Salvin’s albatross being upgraded from nationally vulnerable to nationally critical.