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.
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.
North Island kākā (Nestor meridionalis septentrionalis) often hold food in either their left or right foot when feeding. I observed kākā at Zealandia – Karori Sanctuary in Wellington in order to determine whether kākā show laterality (specifically footedness) when holding food. Laterality was seen at the individual level, i.e. individual kākā tended to consistently use the right foot or consistently use the left foot to hold food. However, there was no significant population level laterality, i.e. a similar proportion of the kākā showed bias towards using the left foot as the right foot. The kākā I studied were banded with a wide band on 1 foot and 2 narrow bands on the other foot. There did appear to be a population level bias towards holding food in the foot banded with the single wide band, but the reason for this was unknown and further study is needed.
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.
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-¹ (se = 0.17, n = 5) along Waipakihi Road and maximum summer flock sizes there averaged 6.0 (se = 1.05, range 2 – 18, n = 19) birds.
I conducted road counts on the North I and South I of New Zealand in Mar 2006 to evaluate relative abundance and distribution of Australasian harriers (Circus approximans). Over 1670 km were traveled on the North I with 98 harriers detected, yielding 1 harrier/17.0 km traveled. Over 2430 km were traveled on the South I with 145 harriers detected, yielding 1 harrier/16.8 km traveled, with no difference in number of harriers detected/km traveled between islands (P > 0.25). Three survey routes, 1 on southeastern North I and 2 on northeastern and east-central South I, were particularly productive yielding 1 harrier/7.1-11.1 km traveled. My results provide empirical support for the frequently cited description that the Australasian harrier is now New Zealand’s most abundant native diurnal raptor, and has largely benefited from the conversion of land from native forest and scrub to pasture at the likely expense of other native and endemic species.
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.
In Jul and Aug 2005, 18 North Is kokako (Callaeas cinerea wilsoni) were released into a 450-ha area of New Zealand native forest subject to intensive control of introduced mammalian predators. The area, Ngapukeriki (near Omaio, Bay of Plenty, New Zealand), lies within a 13,000-ha matrix of native and exotic forest subject to lower and variable degrees of predator control. In contrast to most previous kokako translocations, this project employed 3 tactics to maximise the likelihood that kokako would remain in the target area: 1) many birds were released in a short period; 2) playback of kokako song was broadcast in the release area (potentially creating an “acoustic anchor”); and 3) a kokako pair was held at the release site in an aviary. Most birds approached to within 20 m of playback speakers, some approaching repeatedly. Several interactions between released birds were observed, including vocal interactions and instances of birds associating with one another temporarily. Visits to the aviary pair were rare. On 13 Apr 2006, all 8 trackable birds and 4 birds whose transmitters had failed remained in the core management area; locations of remaining birds (with lost or non-functional transmitters) were unknown. At least 5 territorial pairs had formed, and 1 chick was known to have fledged. To our knowledge, this was the 1st time song playback had been used as an attractant in a terrestrial bird reintroduction.
Natal dispersal of the New Zealand falcon (Falco novaeseelandiae) was documented using relocations of radio-tagged and colour banded falcons in Kaingaroa pine plantation. The age at which fledglings commenced natal dispersal was highly variable. The earliest fledglings dispersed 42 days after fledging, whilst others did not disperse out of their natal territories, remaining there to breed. After 91 days, 87% of fledglings had begun dispersal out of their natal territory. The mean time for the onset of dispersal was 76 days. Males generally dispersed earlier than females, but no significant difference was recorded. Both radio telemetry and colour band recoveries indicated that a large proportion of fledglings dispersed out of the study area. Mean natal dispersal distance within Kaingaroa Forest was 9.6 km. No significant difference was observed in natal dispersal distances between the sexes, although males generally roamed further afield than females. During this study, several females were recorded successfully breeding during their 1st year, a year earlier than usual. Males did not attempt to breed until they were 2 years old. We conclude that the high emigration rates and favourable breeding conditions in pine plantations make these habitats highly likely to act as source populations for neighbouring areas where populations of the New Zealand falcon may be in decline.
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.