The foraging behaviour and success of Australian white ibis (Threskiornis molucca) was investigated in a range of natural and artificial urban habitats in Queensland, Australia. Observations were made in tidal mudflat, freshwater wetland, rural grassland, urban park and landfill habitats. Australian white ibis exhibited a range of foraging behaviours, including both visual (fossicking, jabbing and pecking) and non-visual foraging behaviours (probing). The most common non-foraging behaviour was walking, followed by prey handling, pause and alert. Fighting was observed only in landfill habitats. Australian white ibis were able to capture food items in all habitats, although foraging success at landfills was more than twice as high as the other habitats. Food items captured at landfills required significantly more time to handle before swallowing. The ability of ibis to capture food items in all habitats indicates that they are effective habitat generalists.
Between the 1850s and the early 1900s, most of the native forest of western Taranaki was systematically destroyed. This destruction likely accounted for the disappearance of bellbirds (Anthornis m. melanura), and other native birds, from most of that area. The return of bellbirds to New Plymouth in the 1920s may have been a direct result of increased food that had become available to them there. However, bellbirds have recently become rare visitors to New Plymouth. This may be the result of a possible reduction in the population of bellbirds in nearby Egmont National Park and/or increasing ambient temperatures in cooler months of the year.
North Island kaka (Nestor meridionalis septentrionalis) often hold food in either their left or right foot when feeding. I observed kaka at Zealandia
The distribution and habitat use of New Zealand pipits (Anthus n. novaeseelandiae) in Tongariro National Park on the volcanic plateau of the North I was assessed in Nov 1998 and Mar 1999. Pipits were found at 13 of 22 sites. Surveys between Nov 1998 and Oct 2009 found pipits present all year at Lake Te Whaiau, Mangatepopo Road and Waipakihi Road. Pipits were also seen along the road through the wetland at Erua in winter and summer. At Lake Te Whaiua, pipit presence and use of habitats differed seasonally. The average maximum flock size in summer was 9.7 (se = 1.05, n = 11). Maximum roadside counts outside of the flocking period were 1.13 pipits km-
Singing and territorial behaviour of North Island tomtits (Petroica macrocephala toitoi) were used to monitor population size over a 3-year period at Atuanui, Mount Auckland Scenic Reserve, North Auckland. Male tomtits were observed singing year-round with singing peaking in the period from Nov to Jan. The general territorial behaviour of Atuanui tomtits was similar to that reported for other North Island populations, with territorial males resident in all months and most territories occupied in successive years. Density of territories was stable over the 3-year period but vacancies in suitable habitat suggest the population is not at carrying capacity.
Monitoring of breeding success in 2006/07 and 2007/08, and visits in Dec 2007 to assess levels of stoat predation and burrow densities were undertaken in order to assess the status of Hutton
Tree-cavity nesting is common for a broad range of bird species throughout the world. However, the majority of information on the use of cavity nests is largely derived from the Northern Hemisphere with little data originating from tropical or southern temperate areas. We discuss 3 factors (predation, microclimate, and cavity abundance) that may have shaped the evolution of New Zealand
The effects of a range of habitat variables on spatial variation of breeding burrow density of sooty shearwaters, Puffinus griseus, were measured on 5 islands near Rakiura (Stewart Is) and 1 island in The Snares Is group, during the 2000-01 breeding season. Density estimates for 4 islands where Rakiura Maori harvest chicks ranged from 0.30 to 0.47 burrows per m2. Density on 2 non-harvested islands occurred at opposite ends of the burrow density spectrum (Whenua Hou, 0.09 entrances per m2; The Snares, 0.90 per m2). Burrow density was consistently lower in areas with shallow soil, in inland areas, and where there was more plant debris on the forest floor. The latter may reflect cause or effect because the birds drag woody and leafy debris into their burrows to form nests and to block the burrow entrance. Large amounts of variation in burrow density were not explained by habitat predictors. Detection of harvest impacts on sooty shearwater density on harvested and non-harvested islands will be more powerful if models account for soil depth and island edge-effects, but disregard vegetation variation.
Thirty-one North Island weka (Gallirallus australis greyi) were released on Pakatoa Island (26 ha), Hauraki Gulf, New Zealand in Aug 1996. The population then fluctuated between c.19 and 182 individuals, including c.6-55 pairs. The last of the translocated weka died between Jan and Jun 1998, during a drought and after the rodenticide Talon
A stable evidence-based taxonomy is a critical requirement for the effective future conservation of the albatrosses. Recently published partial molecular phylogenies are in broad agreement with respect to the structure of the evolutionary tree for most named taxa, but the analytical methods used to create them have been seriously criticised and they must be considered provisional at best. A further problem is that their authors reach startlingly different conclusions regarding the numbers of taxa which should be recognised as species; 13 vs. 24. Here, we attempt to resolve this situation by supplying full length mitochondrial cytochrome b data presently missing for 2 taxa, carrying out thorough phylogenetic analyses meeting the requirements of published prescriptions and taking into full account other sources of new molecular data and contemporary opinions on albatross nomenclature and the status of taxa. We provide general support for the published trees and critically evaluate claims regarding how many taxa represent full species. Some genetic distances between pairs of taxa are so small that considerable weight of alternative evidence is required to support any decision leading to a recommendation to split them. We note that the empirical boundary between consensus and controversy falls at or around 1% DNA sequence divergence and further that few, if any, commentators recognise taxa that are separated by less than 0.1% as being valid species.
Conservation management of threatened species (single-species management) is likely to confer benefits to non-target native species, although there are few studies. We examined the relationship between the relative abundance of New Zealand pigeon/kereru (Hemiphaga novaeseelandiae), tui (Prosthemadera novaeseelandiae), grey warbler (Gerygone igata), fantail (Rhipidura fuliginosa) and tomtit (Petroica macrocephala), and intensity of mammalian pest control conducted to protect the endangered North Island kokako (Callaeas cinerea wilsoni) in the Hunua Ranges, 40 km south-east of Auckland, New Zealand. Study areas were subjected to either high intensity (Kokako Management Area, KMA) or low intensity (Milne Stream and Rata Ridge) pest control, and we established 17 monitoring stations per study area and conducted 17 x 5-minute point counts of forest birds in all 3 areas. Abundances of kereru, tui, tomtit, were significantly higher in the KMA. Our findings suggest that single-species management targeted at kokako also benefits some non-target native birds. The contribution of single species conservation management to overall ecosystem integrity is not well understood, and further research is needed to improve the ecological value and cost effectiveness of such management techniques.
The kaka (Nestor meridionalis) is an endemic parrot of New Zealand, and is nationally endangered. Conservation of the species is primarily dependent on intensive control of introduced mammalian nest predators, particularly stoats (Mustela erminea) and brushtail possums (Trichosurus vulpecula). Breeding was studied in 4 sites: Waipapa (1996-2002) and Whirinaki (1998-2002) in the North Island, and Rotoiti (1997-2002) and Eglinton (1998-2002) in the South Island. In total, 145 nests were found. The proportion of radio-tagged females that bred at a site in a given year varied from 0-100%, with most breeding occurring in years of mast-fruiting or seeding by key food tree species. Kaka nested mainly in trunk cavities of live canopy or emergent trees. Egg-laying occurred from Oct to Mar, but differed between years within sites by up to a month, and was usually 2 months later at the most southern site (Eglinton) than elsewhere. Mean egg length was 41.5 mm, mean maximum breadth was 31.5 mm, and fresh egg mass was 22.6 g or 5.65% of female body weight. Clutches consisted of 1-8 eggs, most being of 3, 4 or 5 eggs (mode = 5), and mean clutch size did not differ significantly between the sites. The female alone carried out incubation, with her mate feeding her 8-12 times a day. Overall, hatching success varied from 39-66% between sites, but it also varied between breeding seasons at each site, in part due to the level of control of introduced predatory mammals. Kaka nestlings were covered in white down at hatching, and left the nest when c. 70 days old. Even when 11-20 days old, they were left unattended at night for 20-70% of time and by day for 50-85% of time. Twice females were filmed aggressively attempting to evict stoats that had killed broods in their nest cavities. Breeding productivity (proportion of eggs that produced fledglings) in the 4 study sites varied from 19% at Whirinaki (no control of predatory mammals) to 53% at Eglinton (intense control of predatory mammals). The implications of the breeding biology of the kaka are discussed in relation to conservation management of the species.
Bird nests often contain objects produced and manipulated by other animals, including human rubbish. The function, if any, of these items remains unclear, and it is unknown whether they might serve a signalling role to increase the conspicuousness of the nest lining or contribute to its crypsis. We located several nests of the introduced song thrush (Turdus philomelos) in New Zealand containing discarded cigarette butts. These items were embedded into the dried mud-matrix of the nest and appeared visually inconspicuous to the human observer. However, human and avian visual sensitivities are dramatically different. We used full-spectrum reflectance spectrophotometry, combined with perceptual modelling of the avian visual system to assess the contrast between mud lining, garbage, and the colours of thrush eggs. Our analyses confirmed that, when perceived by birds, cigarette butts were similar in appearance to the nest lining and showed sharp contrast with the eggs. We suggest that cigarette butts form an opportunistic structural component of the song thrush nest. It remains to be determined whether human-made objects in song thrush nests serve anti-predator or an olfactory signalling function. This study illustrates the application of avian perceptual modelling to test signalling based hypotheses for the extended phenotype of birds, including nest architecture.
Abstract Stewart Island/Rakiura, the third largest island in New Zealand, has not had the large-scale forest clearance and introduction of mustelids that has had deleterious impacts on populations of native forest birds on the North and South Islands. However, Stewart Island has had 3 rat species, feral cats and possums introduced, which are known bird predators. It is likely that these species have had serious consequences for the native birds there. As no review of forest birds had been done within the past 80 years, an evaluation of changes in the reported abundance of native bird species on Stewart Island over the past 100 years was carried out, which revealed relatively recent declines and extinctions. Brown teal, rifleman, mohua, South Island kokako, falcon, Stewart Island weka and probably yellow-crown parakeets, have gone extinct on Stewart Island within the past 50 years. Birds showing dramatic declines in the past 100 years include kereru, kaka, kakapo, and robin. Populations of native birds on Stewart Island showed similar patterns of extinctions and declines as the South Island despite fewer agents of decline.