An annotated checklist of the birds of Motu Kaikoura (Selwyn Island) in the Hauraki Gulf, New Zealand, is provided from surveys carried out between Dec 2006 and Jun 2008, supplemented by other recent observations. Thirty-seven species were recorded, including 25 species of land or wetland birds, and 12 species of seabirds and shorebirds. A total of 26 species were indigenous and 11 species were exotic. Motu Kaikoura was gazetted as a scenic reserve in 2004, with ecological restoration a key aim of its management. The 564 ha island has low vegetation diversity, reflecting a long history of anthropogenic degradation. Fallow deer (Dama dama), rats (Rattus spp.), mice (Mus musculus) and feral cats (Felis catus) were present on the island.
Eradication of invasive mammals has been a management priority, with the bird surveys representing baseline data against which the progress of ecological restoration can be measured.
Here I report on a small scale study aimed at generating baseline information on the immune response of wild red-fronted parakeets, as assessed by blood cell counts, and subcutaneous challenge with phytohaemagglutinin (PHA), a mitogen that causes swelling at the point of injection. Eleven parakeets captured in mist-nets were injected into the right patagium with 0.5 mg PHA and the resulting swelling measured at 6 hours post-injection. Prior to PHA challenge, feather and blood samples were collected for detection of beak and feather disease virus and Plasmodium. Blood smears were also prepared for blood cell counts. Swelling occurred 6 hours post-injection in all but one individual, which tested positive for beak and feather disease virus. In this individual, no measurable swelling was detected. Estimated leucocyte counts, lymphocyte counts and heterophil counts of the same individual were similar to values of beak and feather disease virus negative individuals. Plasmodium DNA was detected in 2 individuals and their immune response was similar to that of parakeets testing negative for both beak and feather disease virus and Plasmodium. Estimated leucocyte counts, lymphocyte and heterophil counts did not differ between Plasmodium infected and non-infected individuals. The fact that the only individual testing positive for beak and feather disease virus showed no immune response to PHA challenge suggests increased susceptibility to other pathogenic infections. Although preliminary, this study highlights the potential damaging consequences of the accidental introduction of beak and feather disease virus in conservation programmes of threatened New Zealand parrots, some of which might already suffer from decreased immunocompetence resulting from reduced genetic diversity.
The introductions of mallard (Anas platyrhynchos) to New Zealand, and their breeding and release as a game bird by Acclimatisation Societies are summarised. We identify 19 importations, 14 of which (a total of 115 birds all from Great Britain) were sufficient to establish small feral populations in southern and central New Zealand by about 1910. Five subsequent importations were made by Aucklander C.A. Whitney, 3 from Great Britain in 1910 (6 birds), 1914 (number unconfirmed) and 1927 (393 birds), followed by 99 birds (1937) and 45 eggs (1941) both from the USA. It was Whitney’s distribution of eggs following his initial USA importation that prompted widespread breeding and release programmes which, in some regions, extended into the 1960’s and 70’s. We identify a minimum of 30,000 mallards having been released by Acclimatisation Societies, but numerous releases by private individuals remain unrecorded. Almost all regional Acclimatisation Societies at some time released mallards into the wild.
New bioacoustic technologies offer novel ways to monitor bird populations in the field. Bioacoustic techniques can greatly enhance effective field time, enhance survey site coverage, and increase quantification of key time periods such as crepuscular and nocturnal hours. Moreover, digital files provide searchable, independently verifiable records. Historical impediments to the use of bioacoustics have diminished with unit costs declining and data storage capacities increasing. Recent software developments enable rapid extraction of targeted bird calls and facilitate ease of data analysis. This paper details the recent application of bioacoustic technology at a proposed wind farm site in the upper North I, New Zealand. In this case, bioacoustics were employed as a supplement to on-site field observations and as a complement to avian radar technology. Results illustrate the utility of bioacoustic methods, highlighting the range and scale of potential data outputs. In addition to the detection of flight calls and song, audible wing flap noise may provide a further means of identification for some species. Targeted monitoring of migrant birds, cryptic marshbirds, and rare seabirds are identified as potential future applications.
One-legged standing (or unipedal posture) in birds was investigated with a particular focus on the role of ambient air temperature on this behaviour in a variety of wading birds and waterfowl. Waterfowl (Anas platyrhynchos and Cygnus atratus) were less likely to be observed standing on 1 leg than long-legged species of wading birds (Ardea novaehollandiae, Limosa lapponica, Platalea regia, Himantopus himantopus), perhaps because of differences in the length of their legs. Feeding behaviour and activities associated with disturbance influenced the frequency of unipedal posture. For captive flamingos (Phoenicopterus roseus) and pied stilts (Himantopus himantopus) the proportion of birds observed standing on 1 leg increased as the temperature increased from 8 to 19C. This observation contradicts the theory that unipedal posture is a behavioural adaptation to minimise heat loss on cold days. An alternative theory based on unihemispheric slow wave sleep (USWS) patterns is proposed as an explanation for unipedal posture and is recommended as a focus for future research. Our results also confirm the importance of considering differences between species in leg anatomy and activity levels to measure the effects of temperature.
In a 5 year radiotracking study of 55 falcons on the Wairau Plain, Marlborough, the causes of death in 21 birds were identified. Of these, 10 (47%) falcons were electrocuted (7 juvenile females, 1 adult female, 1 juvenile male, and 1 adult male). Seven of the 10 poles were fitted with transformers. This level of mortality is thought to be too high to sustain a population of falcons. Suggestions are made how to mitigate the problem.
A total of 730 variable oystercatchers (Haematopus unicolor) were recorded during a survey of the entire 1,500 km coastline of the Marlborough Sounds, New Zealand in spring 2006. This included 347 breeding pairs, 28 single birds and a non-breeding flock of 8 birds. The distribution of oystercatchers was influenced by habitat and human development, with fewer birds found in the inner sounds, where there is most development, and in the exposed outer coastline, where cliff or boulder habitat is limiting. Using similar methods of coastal surveys during the breeding season, the estimated national population of oystercatchers has increased from 2000 birds in 1970-71 to 7000 birds in 2006. This represents a population growth rate of 3.5% per annum. Winter flock counts give lower population estimates and coastal surveys are recommended for future monitoring of this species.
Radio transmitters were successfully attached to 7 male bellbirds (Anthornis melanura) in Kennedy’s Bush and Cass Peak Reserve, Port Hills, Christchurch, during the breeding season. A hand-held radio receiver was used to re-locate them. In addition, we used a grid of 4 remote continuously-operating proximity sensors (radio receivers connected to data loggers) to measure the home-range size of 1 bellbird (#7). Five of the bellbirds were detected regularly within 60 m of the site where they were captured. The other 2 were always detected at least 100 m away. Two of the 5 regularly detected near their capture location were occasionally detected 400–500 m away, in gullies with flowering flax (Phormium tenax) and kowhai (Sophora microphylla). The full home range (100% MCP) of bellbird #7 was at least 3.7 ha, and its core home range (90% MCP) was at least 0.2 ha. Its night-time roost was near the centre of its home range. First departure from the roost was before sunrise and last arrival about sunset. If used more extensively, radio telemetry would be useful for measuring home ranges and detecting long-range movements of bellbirds.