I tested the ability of captive black stilt chicks (Himantopus novaezelandiae) to capture and consume common aquatic invertebrates. Waterboatmen (Sigara sp.), segmented worms (Oligochaeta), and larvae of a damselfly (Xanthocnemis zealandica), midge (Chironomus zealandicus), mayfly (Deleatidium spp.), and caddisfly (Aoteapsyche colonica) were captured and consumed quickly and easily by chicks of all ages (2 – 30 days). They were also consumed in the greatest numbers. In contrast, two aquatic snails (Physa acuta and Lymnaea tomentosa) and larvae of two cased caddisflies (Triplectides sp. and Hudsonema amabilis) were captured and consumed with difficulty and in low numbers by young chicks (< 7 days). Young chicks appeared to take longer than older chicks to capture prey, to spend more time manipulating prey in their bills before swallowing, and to drop prey frequently. In contrast, 21 – 30 day old chicks appeared to capture, manipulate and swallow most types of prey efficiently and quickly. These results augment biomass as a measure of the value of aquatic invertebrate food supplies in wetlands.
Population trends in the western weka (Gallirallus australis australis) in Golden Bay and the Marlborough Sounds were examined by field surveys and reference to the literature. Weka declined on the southern margin of Kenepuru Sound in 1995-96, but they were still at 0.10 and 0.06 ha-1 at Big Bay, Endeavour Inlet, and Long Bay near St. Omer, respectively. Weka numbers have declined in lowland Golden Bay to less than 0.01 ha-1 since 1986. The reasons for this declines is unknown, but it appears that high densities of mustelids peaks and climatic extremes are times when weka populations need close monitoring.
Knowledge of the abundance of white-flippered penguins and on the distribution of penguins without attached instruments at sea in general is scarce. Sightings of individual penguins in the neritic waters of southern Banks Peninsula were recorded between November 1993 and March 1997 to document their near-shore distribution and changes in seasonal abundance. White-flippered penguins were not evenly distributed but appeared to concentrate in several bays. Abundance in Akaroa Harbour, the largest bay in the study area, peaked in April and November after recorded lows in March and September (probably due to moult and incubation), respectively.
Waders were counted monthly for six years at the three high tide roosts which are normally used by more than 50% of the waders in the Firth of Thames. The annual cycle of wader numbers is shown for all waders and selected species. The data are used to “correct” wader count data and demonstrate that such “correction” changes apparent population trends. Timing of future bi-annual wader censuses can be improved to maximise counts and/or to minimise variability.
The growth of New Zealand’s second mainland Australasian gannet (Morus serrator) colony at Muriwai, north west Auckland is described from counts between 1975 and 1998. The colonies on Motutara Island, and the southern and northern colonies on Otakamiro Point have increased from 28 pairs in 1975 to 1393 pairs in 1998. The potential for future colony expansion on the northern cliff face, where human disturbance is highest, is discussed.
The number of black-fronted dotterels (Charadrius melanops) in the Ruamahanga River catchment of the Wairarapa, North Island, New Zealand, increased from c. 80 birds in 1972 to 300 – 350 birds in 1996. Another c. 100 birds breed on rivers that drain directly to the eastern coast of the Wairarapa. Their numbers and range are still increasing. Lake Wairarapa is an important wintering site for black-fronted dotterels, although their origin is uncertain.
Twenty four species and two subspecies of bird lice are recorded from New Zealand for the first time. Also, 52 new host-louse associations are listed for louse species already recorded from New Zealand. The genera Cuculiphilus Uchida, 1926, Franciscoloa Conci, 1942, Penenirmus Clay & Meinertzhagen, 1938 and Psittoecus Conci, 1942 are recorded from New Zealand for the first time. Since the publication of the previous list of chewing lice from New Zealand birds, four further lice have been published as new species, and another identified and reported in the literature. One species has been synonymised and its name is deleted from the fauna. Considering the above additions, deletion and other amendments, the total number of species and subspecies of bird lice recorded from the New Zealand region and the Antarctic Ross Dependency is now 301. A further 105 records still remain at generic level only, but all these do not necessarily represent different taxa.
The eastern shore of Lake Wairarapa is a nationally important site for waders. The monthly distributions of eleven species of wader and of white-faced herons (Ardea novaehollandiae) are presented from monthly counts between November 1983 and October 1994. Numbers of spur-winged plovers (Vanellus miles) increased dramatically during this period. Water levels in this shallow freshwater lake vary with regional rainfall, the management of floodgates at the outlet of the lake, and wind direction and strength. Numbers of pied stilt (Himantopus himantopus), banded dotterel (Charadrius bicinctus) and black-fronted dotterel (C. melanops), for which the lake is an important wintering site, declined once the water level rose over about 10.3 m above an imaginary reference point (datum), and also declined below about 9.95 m above datum. Our findings confirm the importance of managing lake levels and we discuss how these data were used in setting operating levels for a water right application to operate the floodgates at the outlet of the lake.
During 1996, participants in the Beach Patrol Scheme patrolled 3071 km of the New Zealand coastline. There were 4649 dead seabirds of 58 species recovered by patrollers. In addition, beach patrollers found 165 birds of 32 non-seabird species. Unusual finds included one Chatham Island mollymawk (Diomedea cauta eremita), one New Caledonian petrel (Pterodroma leucoptera caledonica), two channel-billed cuckoos (Scythrops novaehollandiae) and two spine-tailed swifts (Hirundapus caudacutus). There was a moderate-sized wreck of sooty shearwaters (Puffinus griseus) on North Island west coast beaches in November. The highest annual totals of Pitt Island shag (Stictocarbo featherstoni) and Chatham Island shag (Leucocarbo onslowi) were recorded in 1996. The mean annual recovery rates of Buller’s mollymawks (Diomedea bulleri) and black-billed gull (Larus bulleri) were the highest recorded since the start of the Beach Patrol Scheme. Red-billed gulls (Larus novaehollandiae scopulinus) had their lowest annual recovery rate in 1996. Causes of seabird mortality are discussed in the paper.
Snares Island snipe (Coenocorypha aucklandica huegeli) were studied on the Snares Islands during parts of six breeding seasons between 1982 and 1987. Laying was between 4 November and 19 February; the breeding season (including chick-rearing) spanned the months November to May. Nests were well concealed among dense vegetation with solid overhead cover. Most birds were monogamous, with shared incubation of the two-egg clutch. Males incubated for 51% of the time, mainly at night and during late afternoon; females incubated 49% of the time, mainly during the morning and early afternoon. The eggs hatched synchronously and the chicks stayed in the nest for less than 13 h. The male cared for the first chick to leave the nest. Growth of chicks is described using Gompertz equations. Full juvenile plumage took c. 54 days to attain, and adult size in all growth parameters was attained soon after independence (c. 65 days). Chatham Island snipe (C. pusilla) were studied on Rangatira Island during the 1983-84 breeding season. Laying was estimated to extend from late September to the end of December. Most nests found (86%) were under Carex sedges. Incubation of the two-egg clutch was shared; incubation patterns were not determined. The eggs were 19% smaller in relation to predicted egg-weight than those of Snares Island snipe. The eggs hatched synchronously and the chicks stayed in the nest for less than 11.5 h. The male cared for the first chick to leave the nest. Full juvenile plumage took c. 47 days to attain. The bill grew much more rapidly than for Snares Island snipe and chicks became independent much earlier (c. 41 days old).