Publications Archive

South Island Fernbirds near Invercargill, Southland, were studied for two years. Adult birds had year-round preference for areas with low dense ground vegetation and emergent shrubs. The preferred habitat occurred in a linear strip along an estuary margin. Territories were contiguous and distributed in linear fashion along the strip. Territory areas varied from 530 m2 approximately to 2870 m2 approximately. Territories were strongly defended during the prebreeding and breeding seasons, and defended to some degree at other times. Juveniles were often found outside the preferred adult habitat. There were indications that total Fernbird population needs may include an area adjacent to but exclusive of adult territory areas. Fire had a prolonged adverse effect on breeding habitat.

In 1981, 3,654 kilometres of coast were patrolled by 182 members of the Ornithological Society of New Zealand and their friends, and 5,627 dead seabirds were found. New records for the Beach Patrol Scheme were a Kermadec Petrel (Pterodroma neglecta) and a Long-tailed Skua (Stercorarius longicaudus). Unusual finds were Yellow-nosed Mollymawk (Diomedea chlororhynchus), Wedge-tailed Shearwater (Puffinus pacificus), Wilson’s Storm Petrel (Oceanites oceanicus), Black-bellied Storm Petrel (Fregetta tropica) and Black-fronted Tern (Sterna albostriata). A major wreck of Kerguelen Petrels (Pterodroma brevirostris) and Blue Petrels (Halobaena caerulea) occurred in spring along the western coast of the North Island.

Winter movements of Southern Black-backed Gulls at Palmer Station, Antarctica, correlate with shifts in pack ice. Numbers of gulls increase when open water appears near shore, exposing foraging sites, and when human wastes are available.

Information on flightlines of starlings (Sturnus vulgaris) to and from roosts is summarised, and a map shows sites and areas served by roosts in the Wellington area. Four offshore islands in the area are used as roosts. In midwinter birds may spend 16 hours nightly in roosts. One roost has remained in use since at least 1913, and others have shifted or been used intermittently. The number of starlings flying to the major roosts in the region has fallen during the 1970s.

Grey Warblers (Gerygone igata) at Kowhai Bush, Kaikoura, apparently moulted once annually – between January and March. They nested in 19 kinds of trees and shrubs – mostly small-leaved species, especially kanuka, the dominant plant in the study area. Behaviour associated with selection of the nest site is described. A list of materials used in building is given. On average, nests were 14 cm long and just over 7 cm wide. Nearly half the nests hung freely from their upper attachment; others also had attachments laterally and below. The entrances of nests were non-randomly orientated in 1976 but not so as to face away from prevailing winds. Copulation is described. Three eggs in September were laid close to sunrise. Late eggs were wider on average than early ones but no different in length. The constant that related fresh weight of eggs, length, and the square of width was 0.598. Eggs lost about a quarter of their weight during incubation. Grey Warblers hatched with natal down distributed in eight main and two minor patches. The physical and behavioural development of nestlings is described. A sample of 19 nestlings had been fed invertebrates of six orders. Caterpillars occurred in 90% of stomachs and made up 42% of ingested items. Spiders were next most important of total items. Nestlings were parasitised by the blood-sucking mite Ornithonyssus bursa. Fledglings had distinctive dark brown irides and yellowish facial plumage until February-March, when they moulted to adult form. Males played the greater role in caring for early fledglings while the female built the late nest. Young males seemed rarely to be successful in holding territory the summer after that in which they were reared. Brood parasitism by Shining Cuckoos was the main cause of failure of late eggs (though a relatively minor factor overall); mammalian predation was the greatest single cause of nestling mortality.