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Preliminary report on damage to coconuts and on the ecology of the Polynesian rat (Rattus exulans) in the Tokelau Islands

Extensive trapping shows that the Polynesian rat (Rattus e. exulans (Peale)) is the only rodent present in the Tokelau Islands and that it is responsible for damage to coconuts. Green coconuts 5-25 cm. long are gnawed on the palms and subsequently fall to the ground and disintegrate. Damage was assessed by counting damaged and undamaged nuts in quadrats on various islets of the Nukunonu and Atafu atolls. The numbers of rats on these islets were assessed by using the capture-mark-recapture method.

Opossum research in the Orongorongo valley, Wellington

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A population of approximately 200 opossums (Trichosurus vulpecula) in 60 acres of indigenous forest in the Orongorongo Valley, Wellington, has been intensively live-trapped since February 1966. Frequent recapture of ear-marked animals has provided information on movements, population size, sex ratio, colour phases, physical characteristics, reproduction and growth and development of young.

Factors controlling irregular flowering in four alpine species for Chionochloa

Irregular flowering occurs in at least nine alpine species of Chionochloa and, moreover, their flowering seasons usually coincide. Transplanting experime::lts with four of these species (C. crassiuscula, C. flavescens, C. oreophila and C. rigida) indicate that their flowering is largely controlled by the environment, although availability of reserves is probably also important.

Environmental effects on the sex ratio of Rumex acetosella L.

Observations on the ratio of staminate to pistillate individuals of Rumex aeetosella from a variety of sources indicate the predominance of males. Results from forty-four sites in the South Island of New Zealand suggest the sex ratio is affected by the environment, and this is related to differences in the intensity of competition at roadside, new pasture and tussock grassland sites. Results for the sex ratio are related to the height differences between staminate and pistillate individuals.

Dispersion and dispersal of the Dominican gull in Wellington, New Zealand

The basic population structure of the Dominican gull, Larus dominicanus, in Wellington, New Zealand, was examined by total censuses, fixed transects, and by banding. A census during the period of peak autumn population in 1965 revealed 12,236 in the Wellington area, and over 84% within II miles of the harbour. There was an average of 48.5 birds/mile of coast; 48.8% of all gulls were at or near refuse tips or meatworks. On mainly uninhabited coast there was an average of only 2.4 birds/ mile, showing the distribution of the species is now greatly influenced by human occupation.

Some ecological aspects of the spawning behaviour and early development of the common whitebait, Galaxias maculatus attenuatus (Jenyns)

A spawning locality for Galaxias maculatus attelluatus (Jenyns) is described. Details are given of spawning movements and dates for 1959-62 and 1967. The complex relationship which must exist for a freshwater fish (albeit with a marine larval phase) to move downstream only at such times that it will reach estuarine areas at spring tides is examined.
Spawning habits and the conditions under which the eggs develop and the rate of development at different temperatures are described. An attempt is made to coordinate three studies of the spawning behaviour of this species.

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