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.
Seasonal variation in size of duck populations was examined using weekly surveys along a 1.5 km section of the Waihopai River, Invercargill, New Zealand, between Jul 1995 and Jul 1996. Six species were recorded: mallard (Anas platyrhynchos) (n = 8307), New Zealand shoveler (A. variegata) (n = 285), grey duck (A. superciliosa) (n = 36), paradise shelduck (Tadorna variegata) (n = 4), grey teal (A. gracilis) (n = 1), and New Zealand scaup (Aythya novaeseelandiae) (n = 1). Asynchronous seasonal trends were observed for mallard/grey duck and shoveler populations: mallard/grey duck numbers peaked during duck hunting season, whereas New Zealand shoveler peaked just prior, and declined during hunting season. A relatively constant rise in mallard/grey duck from Jan to late Jun highlights the difficulties in distinguishing the relative effects of post-breeding moult congregations vs. dispersal to refugia from hunting–related disturbance.
Few places have been as ecologically devastated by the introduction of exotic mammals as Phillip Island in the Norfolk Island Group. Pigs (Sus scrofa), goats (Capra hircus) and rabbits (Oryctolagus cuniculus) denuded the island so severely that massive amounts of soil and underlying substrate were lost through erosion. Rabbits, the last of these exotic animals to be removed, were eradicated during the 1980’s. Since then the extent of vegetation on the island has been increasing by natural revegetation and through plantings and seeding. Fourteen species of seabird currently breed on Phillip Island. Five species—Providence petrel (Pterodroma solandri), Kermadec petrel (P. neglecta), white-naped petrel (P. cervicalis), flesh-footed shearwater (Puffinus carneipes) and red-tailed tropicbird (Phaethon rubricauda)—all have ecologically significant populations. In this paper, we review the current status of the seabird populations breeding on Phillip Island, and suggest how vegetation restoration is likely to affect each species. We update previously published notes and present unpublished material collected by us over more than 3 decades. We document when each species was first discovered, reveal the location of nesting sites, describe breeding phenology and nesting habitat, report on any banding activities and returns, and discuss potential threats.
A total of 57 reef herons (Ardea sacra) were counted during a survey of the entire 1,500 km coastline of the Marlborough Sounds in spring 2006. Most birds were encountered in the outer part of the sounds rather than the more developed inner sounds. The total New Zealand population is estimated at 300-500 birds. Both the Marlborough Sounds and national population appears to have been stable for the past 40 years. With a small but stable population the reef heron’s threat classification in New Zealand should be changed from Nationally Vulnerable to Naturally Uncommon. The species is secure overseas with New Zealand being the southernmost limit for the species.
A survey of the entire 1,500 km coastline of the Marlborough Sounds between Sep – Dec 2006 located 9 king shag (Leucocarbo carunculatus) breeding colonies, including 2 new colonies. The total population was estimated at 687 birds, a figure similar to the 10-year average estimated for the period 1992-2002. The 4 largest colonies supported 85% of all birds recorded. The total population appears stable compared to earlier surveys, but there was a tendency for some of the smaller breeding colonies to be occupied only temporarily.