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 We update previously published notes and present unpublished material collected by us over more than 3 decades.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.
Using GPS technology, we tracked 3 juvenile northern royal albatrosses (Diomedea sanfordi) as they fledged from Taiaroa Head, Otago Peninsula, New Zealand. All birds flew north along the east coast of New Zealand before undertaking a trans-Pacific easterly migration to Chile. During their 8500 km migration, the maximum daily distance and speed reached were 1047 km and 110 km h-1, respectively, and the maximum altitude was 38 m a.s.l. Upon leaving New Zealand waters, the 3 albatrosses took between 16 to 34 days to reach the coast of Chile where they remained between 23°S and 58°S. The tracked albatrosses generally kept to within 100 km of the coast where the depth of water varied between 1000 and 2000 m. Overall, the tracked albatrosses on the Chilean coast spent 72% of the time resting on the water, primarily between 1800 h and 2400 h local time. Fix success rate of the GPS technology ranged from 56% to 85%. The use of solar charging and a long attachment period allowed birds to be followed continuously for 134 to 362 days. Our study confirms the value of GPS technology in uncovering the movements and life history of wide-ranging oceanic birds.
Silvereyes (Zosterops lateralis) in an urban population in Marlborough, New Zealand showed considerable diurnal changes in body mass. At first light, average mass was 12.39 g, rising to 13.91 g by dusk. This represented a 12% average loss of mass overnight. The overall average mass was 13.22 g; birds were 6% below average at 0700 h, but increased rapidly to be near the average for most of the day, rising significantly in the 2 hours before dusk (1700 h). This pattern of diurnal mass change is consistent with theoretical models suggesting that birds should manipulate daily mass gain in order to trade-off starvation risk with mass-dependent predation risk.
We document hybridisation between South I pied oystercatcher (Haematopus finschi) and variable oystercatcher (H. unicolor) in Canterbury from 1989 to 2005. From 2 observations of hybridisation between South I pied oystercatcher x variable oystercatcher when first discovered, the hybrid swarm has increased to around 17 pairs, including South I pied oystercatcher pairs, variable oystercatcher pairs, hybrid pairs, and mixed pairs. We present data on the birds and their offspring and speculate on possible causes and implications of hybridisation for conservation of the taxa.
Evidence from Cook’s voyages supports the late prehistoric human introduction of the red shining-parrot (Prosopeia tabuensis tabuensis) from Fiji into the Tongatapu group, Kingdom of Tonga. It appears that a wild population of red shining-parrots was established on ’Eua by the time of Cook’s visits to the Tongatapu group in the 1770s. Latham used specimens obtained at ’Eua in 1777 for the 1st published description of the species. However, the correct type locality of the taxon is Fiji. A red shining-parrot specimen used by Latham is in the Naturhistorisches Museum in Vienna. It is 1 of the few bird specimens that survive from Cook’s voyages.
Prey remains and regurgitated pellets of New Zealand falcons Falco novaeseelandiae, from Adams I in the Auckland Is, were collected to determine the diet of this species in the subantarctic part of their range. Dissection of pellets revealed 1588 bones from 215 individuals of 18 species of birds preyed upon. Feathers associated with the remains supported the bone identifications. Rangle stones were also collected. The presence of procellariiform seabirds in the diet of falcons suggests some nocturnal hunting. While the single most frequent prey species was the bellbird (Anthornis melanura), Antarctic prion (Pachyptila desolata) and subantarctic diving petrel (Pelecanoides urinatrix exsul) were also common. When measured by prey weight, endemic land birds such as Auckland I rail (Lewinia muelleri), Auckland I snipe (Coenocorypha aucklandica aucklandica), and Auckland I teal (Anas aucklandica) constituted a third of the prey. Like many island birds, these ground-dwelling species cannot co-exist with introduced mammalian predators, but survive despite predation by native falcons.