We counted the black shags (Phalacrocorax carbo) frequenting a night roost at Melling, 4.5 km up-river from the Hutt River mouth, Wellington, New Zealand, and studied the timing of breeding at various colonies in the Wellington region. Numbers at the roost were counted from Oct 1993 to Sep 1998: maximum and minimum mean monthly counts were in Feb and Aug, respectively. The main egg-laying period of 3 coastal colonies (0–2 km) (Mar–May) was c. 3 months earlier than at 2 inland (5 – 33 km) colonies (Jun–Aug. We discuss the possibility that the difference in timing of breeding by shags in colonies at different distances from the coast is related to the different timing of peak prey availability in the 2 habitats (coastal marine, and inland riverine).
From satellite tracking data, we recognised 5 major flight patterns in the annual cycles of 3 Chatham albatrosses (Thalassarche eremita) tracked in 1997 and 1998: foraging flights while the birds were breeding; eastward and westward migrations across the southern Pacific Ocean; northward migration along the South American coast; and localised foraging at low latitudes off the northwest coast of South America. We hypothesised that the 5 modes of flight indicated different biological activity. The associated speeds, point-to-point distances flown day-1, and other indices of activity were inferred from distances and times between satellite location records. Mean minimum point-to-point flight speeds were up to 85 km h-1 and were a function of the time interval for the measurement. Daily rates of change for latitude and longitude and the minimum daily distances travelled were calculated. These are the 1st measurements for this species of the sustained speed of flight point-to-point over varied time periods, and for short and long distances throughout the year. These data and the analytical techniques developed show what information can be obtained from a few individuals, and the confounding variables that result from the satellites’ orbits, and the transmitting characteristics of long-duration PTT experiments. The interrupted reception of transmitters through the intermittent satellite passes biases speed and other measurements and difficulties interpreting these data are discussed. The results provide a guide to the design of satellite transmitter experiments for long distance and duration studies with other oceanic species. They also contribute to an understanding of where this species obtains its food, and of its potential risk of interaction with fisheries.
A massive northward movement and wreck of prions (Pachyptila) along the coast of Antofagasta, Chile is described, and I review the occurrence of prions along the west coast of South America. Prions breed in southern Chile and the sub-Antarctic and move northwards to the coasts of northern Chile and Peru in the Southern Hemisphere winter. Chilean and Peruvian wrecks are primarily P. belcheri, with smaller numbers of P. desolata. P. vittata has only been recorded once. The occurrence of P. salvini is unproven. There are no records of P. turtur; a purported specimen from Chile is actually P. belcheri. The only report of P. crassirostris is that of a bone fragment from an archaeological site on Easter Island, Chile.
Roost sites in Whangarei Harbour and Ruakaka Estuary were used regularly by 12 wader species and 6 other species were present occasionally between 1974 and 2000. Counts at 7 roost sites in Nov, Jun/Jul, and Mar showed that 4 species, eastern bar-tailed godwit (Limosa lapponica), lesser knot (Calidris canutus), pied stilt (Himantopus leucocephalus), and South Island pied oystercatcher (Himantopus ostralegus finschi) contributed 70–99% (median 94%) of the waders. Most of the common waders used several roosts at each tide, but numbers and species richness of resident and vagrant species were greatest along the southern margin of the harbour. Changes in roost structure and proximity to feeding areas, and differences in migration patterns affected counts at individual roosts and the overall totals of wading birds counted in the harbour and its environs.
We report the 1st use of a satellite transmitter to track the endemic New Zealand falcon (Falco novaeseelandiae). The movements of an adult female bush falcon in Kaingaroa Forest east of Lake Taupo, central North Island were monitored during a 3-year period from Feb 2002. The geolocations of the falcon were mapped and revealed that the falcon remained close to her nesting territory throughout the study. The home range included an area of c. 200 km2. The falcon nested in pine compartments (0–3 years old) for 3 consecutive years; her nests averaged 5 km apart. After nightfall the falcon was located within the 95% isopleth of her home range, highlighting her sedentary nature. During the breeding season the falcon appeared to wander outside of her home range, with the furthest recorded distance from its centre being 137 km. Throughout the 3 years, observations suggest the falcon preferred to stay close to open areas, which may be related to the frequency of hunting opportunities.
Following the translocation of North Is kokako (Callaeas cinera wilsoni) to Kapiti I, southern North Is, New Zealand, Department of Conservation staff noted that most pairs were forming between individuals that came from the same source origin. This study investigated whether geographic variation in dialects influenced mate selection and, ultimately, pair formation on Kapiti I. Between Nov 1999 and Mar 2001 songs of male kokako that had paired and were resident at a single site were recorded. In addition, recordings were obtained from the Department of Conservation of birds in the source areas. Analysis of the songs indicated that kokako songs were typical of their areas of origin at the time of translocation and differed from songs of birds from different source areas. Translocated female kokako preferentially chose males whose repertoire was typical of the acoustic environment they experienced before translocation. Song analysis and pair formation of kokako born on Kapiti I indicates that the observed assortative mating was a temporary phenomenon in the years after translocation, which did not continue following juvenile recruitment.
New Zealand average atmospheric temperature showed little increase from the 1850s onwards for almost 100 years, but increased rapidly after c.1940. The increase in temperatures was accompanied, at least in parts of New Zealand, by an increase in precipitation,. We investigated the relationship between the arrival years (1st breeding) of the bird species that self-introduced to New Zealand during the 20th century and the period of turpentine increase. Because these birds come from Australia the warming might be a prerequisite to colonize New Zealand. When considering the 1st breeding years as events in a univariate point process the process is non-stationary and the rate function has its estimated maximum in 1953. This estimate may indicate that the sequence of invasions of New Zealand by additional bind species could be a response to climate changes although the coincidence is on its own not sufficient to prove that climate changes have affected the self-introduction of birds from Australia into New Zealand. Alternative and additional explanations are discussed.