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When interpreting counts of forest birds it is seldom possible to distinguish the effects of changing density from those of changing conspicuousness; these often arise from the birds’ singing and calling. To investigate this, birds first seen were recorded separately from those first heard when counting birds in forest of the Orongorongo Valley, Wellington, New Zealand. Apparent changes in the frequency of Paradise Duck (Tadorna variegata) in the river valley, and of the Song Thrush (Turdus philomelos), Whitehead (Mohoua albicilla), Grey Warbler (Gerygone igata) and Chaffinch (Fringilla coelebs) in the forest coincided with changes in the frequency of their singing or calling; they were considered suspect. Changes in the frequency of the Black-backed Gull (Larus dominicanus) on the riverbed, and of N.Z. Pigeon (Hemiphaga novaeseelandiae), Blackbird (Turdus merula), Fantail (Rhipidura fuliginosa), Silvereye (Zosterops lateralis), Bellbird (Anthornis melanura), Tui (Prosthemadera novaeseelandiae), and Australian Magpie (Gymnorhina tibicen) did not show a similar correlation. Special study of the ways in which birds either advertise or conceal themselves is needed. Correction factors may never compensate completely for the effects of the birds’ varying conspicuousness.

Captive Weka (Gallirallus australis) were offered two species of native frogs (Leiopelma hochstetteri and L. archeyi) as prey. The anti-predator behaviour and/or gland secretions of the frogs were sufficient to avoid damage and allow them to escape. The leaf litter habitats where frogs occur in the Coromandel Ranges are least likely to be favoured by Weka. Objects under which frogs were found were heavier than those generally moved by Weka while foraging. Weka seem to constitute less of a risk to frogs than earlier believed.

We studied Cape Pigeons Daption capense at The Snares, one of its northern most breeding sites, from pre-laying to fledging during 1985/86 and 1986/87, and compared our data with those from other localities. At The Snares, mean laying dates were 10 November 1985 and 8 November 1986, mean hatching date was 25 December 1985, mean fledging date was 14 February 1986, breeding success was 58.7% in 1985/86 and 50.0% in 1986/87, and adult male annual survival was 94%. Laying mainly begins later at higher latitude breeding sites and there are differences in pre-laying colony attendance between some populations. Incubation and nestling periods are similar throughout the species’ range suggesting an inherent rather than environmentally-induced explanation for the relatively short nesting season of fulmars compared to other petrels.

During a census in gardens in Hamilton, 71.8% of the 4428 birds observed belonged to introduced species. A total of 15 species were observed. Bird species richness was positively correlated with native plant biomass and, more strongly, with total plant biomass. More birds were present in gardens with more native plants. Among the most common species, the abundance of the House Sparrow (Passer domesticus) decreased with increasing percentage of native plants, the Silvereye (Zosterops lateralis) increased, while Blackbirds (Turdus merula) and Starlings (Sturnus vulgaris) showed no significant change. This was typical for a other introduced bird species. Most other birds, including the Fantail (Rhipidura fuliginosa) and the Grey Warbler (Gerygone igata), were most abundant in gardens with higher native plant biomass. Notable was the absence of the Tui (Prosthemadera novaeseelandiae) from all censused areas in Hamilton at the time of observation. No significant variation between morning and evening samples was noted.

During a visit to North Brother Island in Cook Strait from 11 October to 6 November 1990, we estimated by quadrat sampling that the 4 ha island supported 1000 pairs of Fairy Prions, 600 pairs of Common Diving Petrels, and 225 adult tuatara. Most Diving Petrels nested below Coprosma scrub, and a few eggs were laid on the surface under dense shrubs. Many prion burrows were in more open vegetation. Burrows of both species were simple and were not shared with tuatara. Some evidence of tuatara preying on unattended eggs was found, but there was no evidence that the endemic Sphenodon guntheri, which is smaller than S. punctatus, fed on adults of either species. Many Diving Petrels, prions, Fluttering Shearwaters and Red-billed Gulls fed in tide rips close to the island. The position of each species in feeding assemblages was related to their dive depths. Diving Petrels in areas of strong currents submerged for only a few seconds at a time, but in areas of calm water dive durations averaged 29 seconds.

Pipit (Anthus novaeseelandiae) numbers on nine count routes in the Wellington region ranged from 0.16 to 6.22 per km on average. Estimated densities in regions with some favourable habitat varied between 1.0 and 2.5 per square kilometre. Highest numbers were in the hills south and west of Karori, and on the southern and western beaches between Owhiro Bay and Titahi Bay. Densities were lower over the rest of the region due to intensive farming, unfavourable plant succession pathways to bush, and urban development.