Birds were counted in four forest areas every second month of a year to determine broad habitat preferences of the different species and the factors affecting the numbers counted. Most species showed marked seasonal changes in conspicuousness. The differences between the numbers of birds counted by different observers were generally small compared with the differences between areas and seasons. Many species were more abundant in the valley-bottom forest than in the two hill-country forests; only a few species preferred high-altitude forest. The preferred habitat of some species changed with season. The implications of these findings for bird conservation in Westland forests are discussed.
The breeding and habits of the Antarctic tern (Sterna vittata) were studied during a summer at the Snares Islands. Daily records were kept of ten nests situated on cliff ledges and rocks. Egg-laying occurred during two periods; late October/early November and late November. The usual clutch was one egg, but some two-egg clutches were laid. Re-laying probably occurred on one occasion when the first clutch was lost. Both parents incubated, and the incubation period averaged 24 days. The chicks were guarded for two to three days after hatching and were fed by both parents. Chicks fledged between 27 and 32 days after hatching. Adverse weather severely restricted chick growth during the early stages of development and was a major factor in chick mortality.
Factors causing predation of the clam paphies (Mesodesma ventricosa), the well-known ” toheroa,” by black-backed gulls are described. Counts of black-backed gulls made at approximately monthly intervals along a 23 kilometre stretch of beach between January 1970 and January 1971 and in December 1972, together with further observations between 1968 and 1975 show that black-backed gulls are important predators of toheroa.
Results are given of a monthly survey of birdlife in the subalpine Lake Harris basin, north-west Otago Alps. Fluctuations over a year, from May 1976 to April 1977, were tallied by species and by numbers of individuals. Comments are made on effects of climatic conditions and resources available to birds at such altitudes in the Southern Alps along the Main Divide. Arising from observations made so far, it is suggested that the rock wren (Xenicus gilviventris) may hibernate during harsh winter months.
During 1976, 2,826 kilometres of coast were patrolled by 151 members of the Ornithological Society of New Zealand and their friends. 5,990 dead seabirds were found. There were no major wrecks. A number of minor wrecks involving blue penguins (Eudyptula minor), white-headed petrels (Pterodroma lessoni), sooty shearwaters (Puffinus griseus) and fairy prions (Pachyptila turtur) are recorded. White-faced storm petrels (Pelagodroma marina) were found in higher numbers than ever before particularly on Canterbury South beaches. Patrols of Mason’s Bay, Stewart Island, were the major factor contributing to the highest ever total of mottled petrels (Pterodroma inexpectata). The grey ternlet (Procelsterna cerulea) found is a second record and the black-fronted tern (Chlidonias hybrida) a new record for beach patrolling. The Christmas Island shearwater (Puffinus nativitatis) found is a new record for the New Zealand region.