Kowhai Bush in the Kaikoura region represents an important wildlife reserve for some native forest bird species. It is home of 1 of the few populations of brown creepers (Mohua novaeseelandiae) and South Island robins (Petroica australis) in lowland forest in the Canterbury region. Here, I present results from 275 five-minute point counts that were conducted at Kowhai Bush from October until December from 1999 to 2001. I compare these data with those collected by Gill (1980) in the same months of 1976 at similar sites. These comparisons reveal that the observed abundance and composition of the species at Kowhai bush has changed between 1976 and 1999-2001. Overall, there was a decline in bird abundance between 1976 and 1999-2001 and there was a significant difference in bird abundance between the 2 habitats in which counts were undertaken at Kowhai Bush. At a species level, there were dramatic declines (>50%) in the observed abundances of brown creepers and South Island robins whilst blackbirds (Turdus merula), redpolls (Carduelis flamea), and European goldfinches (C. carduelis) had more modest, but still significant declines. These declines were offset somewhat by large increases (>50%) in the observed abundances of silvereyes (Zosterops lateralis), and song thrushes (Turdus philomelos) and significant increases in the observed abundances of bellbirds (Anthornis melanura) and chaffinches (Fringilla coelebs). I discuss a number of factors that might be responsible for these changes.
Mohua (Mohoua ochrocephala) are endemic to the South Island of New Zealand but they have declined in both range and abundance. The causes of decline include predation from introduced predators and forest clearance. Mohua have survived in reasonable numbers in the Dart Valley in west Otago. In this paper we describe the relationship between the presence of mohua breeding territories and vegetation at a 1 ha scale within low altitude, red beech-dominated forest. The extent of shrub or regeneration was found to have the strongest association with the presence/absence of breeding mohua. Other factors which increase leaf volume, such as forest-edge and broken canopy were also important in explaining the presence of mohua. Milling was found to have a long lasting negative impact (>70 years) on mohua presence. Management which reduces grazing and increases the shrub and regeneration forest component is likely to increase mohua carrying capacity.
Home range size, travel distances, and population density of the great spotted kiwi (Apteryx haastii) were investigated in the North Branch of the Hurunui River. Radio tracking was conducted on 10 great spotted kiwi between Dec 2007 and Apr 2008. The estimated minimum home-range sizes were determined using the concave polygon method and ranged between 19.6 ha and 35.4 ha, with a mean of 29.3 ha (± 1.6 SEM). The observed nightly distances travelled per hour varied from 7 to 433 m (n = 569). Most estimates of travel distances (73%) were clustered in the classes from 0 – 150 m/hour, and distances over 200 m/hour were seldom achieved (only c. 7% of distances). The kiwi population in the Mainland Island site on the western North Branch of the Hurunui River was estimated to hold around 290 birds in total. Population density for the entire North Branch area was estimated to be 2 pairs/km² and when including subadults, 5 birds/km². Our estimate of home range size is larger but with more variation than found in other studies. Differences in population density estimates between our study and those in the Hurunui and Arthurs Pass district may be due to different objectives and methods.
Information on the relevant spatial scale for controlling pest birds causing significant crop damage is generally lacking. Here, we assess the potential of 2 radiotracking systems (hand-held vs. elevated twin-Yagi antennae) for monitoring pest bird ranging behaviour on and around an arable farm. Radio-transmitters were fitted to 19 European greenfinches (Carduelis chloris) in the summer and 25 house sparrows (Passer domesticus) in the winter. Greenfinches were most likely to be detected in or near Brassica seed crops, particularly on the study farm, but 12% travelled large distances (>3 km) between Brassica crops in the landscape. Even though house sparrow home ranges were widely dispersed across the landscape, most overlapped with the farm boundary and were positively associated with woody vegetation. Relative to hand-held antennae, the elevated twin-Yagi system increased the detection radius for tagged birds from 100 m to 2000 m and also the number of location data, albeit over a more restricted area.
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.
One significant late Holocene deposit of bird and other fossils was discovered during a brief survey of potential fossil sites on subantarctic Campbell I, New Zealand. The bones recovered included the first specimen of a Cyanoramphus parakeet from the island. Preliminary ancient DNA analysis of the parakeet bone confirmed its generic identification and may ultimately facilitate the re-introduction of a taxon that most closely resembles the genetic make-up of the extinct population. Some implications of the fossil record and value of the fossil sites are discussed.