To date there has been no published information describing the relative abundance, behaviour or distribution of the New Zealand king shag (Leucocarbo carunculatus) within mussel farm areas, despite the sensitivity of the species to human disturbance and the potential overlap of its range with proposed development of marine aquaculture. Four survey methods were employed as part of a multi-species research programme to develop methods for surveying marine mammals and seabird populations in aquaculture management areas. Two of the techniques, involving continuous time- lapse photography of mussel farms and boat-based surveys through coastal farms were developed for this study. Time- lapse cameras showed that mussel farms buoys were used by king shags as temporary resting sites only. King shags were recorded on 36% of the farms (n = 44) from 13 surveys within inner Admiralty Bay. The low number of sightings within mussel farms suggests that farms are not important foraging or resting areas for king shags, at least in Admiralty Bay. The foraging range and density of king shags was not known before farms were developed, so no direct comparison or impact assessment can be made. Boat-based surveys were used to estimate the density of foraging shags, which showed that daily locations of foraging birds at sea can vary considerably on consecutive days and over the season. Previous environmental surveys to assess impacts of mussel farms on foraging areas are therefore unlikely to adequately represent the entire foraging range or most important feeding areas. The number of breeding pairs, chicks and nests was also found to vary considerably at colonies, dependent on when counts were undertaken during their protracted breeding season. Open water mid-bay aquaculture (shellfish and finfish) potentially poses a greater threat to king shags than ‘coastal ribbon development’, in terms of loss of open water habitat from farm structures, and loss of foraging habitat through modification to the water column (e.g., turbidity) and seabed. Given the lack of knowledge about the king shag population dynamics, diet and prey availability, there is an urgent requirement for more research to fill these gaps and also understand how we can conserve important shag feeding areas and associated marine environment through sustainable management of aquaculture.
Sexual differences in vocalisations of the Vanuatu petrel (Pterodroma occulta) are described. Qualitative differences in burrow calls could be used to sex adults with 63-100% accuracy in listening experiments. Males sounded “clear” and females sounded “hoarse”. Higher accuracy is possible with the aid of spectrograms. Playback experiments demonstrated a male-bias in responses of incubating Vanuatu petrels to “war-whooping” and flight calls. Acoustic methods have practical and ethical advantages over handling breeding petrels and further studies of the vocal behaviour of gadfly-petrels are encouraged.
We investigated the population size and annual survival of Salvin’s albatrosses (Thalassarche salvini) breeding at the Western Chain, The Snares, New Zealand. A count of breeding pairs during incubation resulted in totals of 1100-1200 breeding annually on Toru and Rima Islets in the 3 years 2008-2010; none was seen breeding on Tahi, Rua or Wha Islets.The majority of adults bred annually. Based on banding and recapture the annual survival probability of breeding birds was estimated to be 0.967 while that of known-age birds banded as chicks in Feb 1986 was estimated at 0.939. A bird banded as a chick on the Bounty Is in 1985 was found breeding on Toru Islet of the Western Chain in the 3 years 2008-2010. This is the first record of a banded Salvin’s albatross breeding away from its natal island.
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.