Publications Archive

Four colonies of black-backed gulls (of which onIy the three main ones are considered extensively) exist in the close proximity of Cape Kidnappers. While gulls move extensively within the area, no, large increase in numbers has been noted between 1959 and 1963. Distinct gull movements, or “patrolling” have been observed near all gannetries at Cape Kidnappers. Mainly adult birds are concerned in this activity.

Edible matter, in particular regurgitations or eggs, may be taken by gulls from the Cape Kidnappers colonies, as elsewhere, if the opportunity occurs during “patrolling ” movements in the air or “parading” on land. The placing of Plateau Colony B on a grid has shown empty nests on the periphery. It was found that the gannets nesting in the centre of the colony had the highest percentage nesting success and returned earlier for the breeding season.

Banding has established that young pairs of gannets arrive later at the gannetries, nest on the outer margins of the colony, and have smaller nesting mounds. This marginal area also coincides with the main areas of movement by tourists. Figures from 1945–62 indicate a steady increase in the gannet population of the Plateau gannetries. Because of publicity an increasing number of the public are visiting the gannetries each year. With gull populations at their present levels, there is no evidence that black-backed gull predation is having a depressing effect on gannet numbers.

North Island wekas, once plentiful, became almost extinct approximately 40 years ago, leaving only a small residual population in the Gisborne – East Coast area and Northland (Waipu). Since then, they have multiplied rapidly in the vicinity of Gisborne and are now abundant in that part of the country. Over a period of 18 months 94 wekas were collected from the Gisborne district for study. Gizzard contents were examined and were found to consist of vegetable matter, seeds, insects and other small invertebrates and occasional1 birds’ eggs and frogs. Predominant items of diet were of plant origin – grass, fibrous material, small pieces of wood and clover leaves. A wide variety of seeds was found, most common being of the grass family, with clover and sedge next in order of importance, Insects predominated in the animal food taken, the most important being beetles, wetas and grasshoppers. Earthworms also were a major item of diet, while insect eggs and millipedes were frequently found.

From nesting records and gonad measurements a study was made of the breeding cycle. It appears that, although breeding occurs throughout the year, it reaches a peak during winter and early spring (June to September). Wekas commonly raise more than one brood in a year; up to four have been recorded. The average number of eggs in a clutch is 3-4, although 5 or 6 are not abnormal.