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Breeding behaviour and ecology of the Australasian harrier (Circus approximans) in the Manawatu-Rangitikei sand country, New Zealand

Notornis, 28 (2), 103-119

Baker-Gabb, D.J. (1981)

Article Type: Paper

During 1976-78, 212 Australasian Harriers (Circus approximans) were trapped and individually marked, and a total of 220 retraps and 319 resightings were made. During two breeding seasons the population density averaged one bird per 50 ha. Seven territories averaged 31 ha each, and the home ranges of four pairs averaged 900 ha each. Some of the behaviour and displays described have not been previously recorded for the Australasian Harrier, including territory-boundary display flights, border patrolling, eviction of intruders, nest inspection, courtship feeding, copulation, and post-fledging behaviour and dispersal. Also described are display soaring, display diving, feeding at plucking stations, aerial food passes and the post-hatching parental division of labour. Nineteen pairs fledged an average of 1.0 young per nest site and 1.8 young per successful nest. Birds observed breeding at Pukepuke Lagoon for a second consecutive season were more successful than new arrivals. Two cases of polygyny were observed.

The New Zealand dabchick on Lake Rotoiti

Notornis, 28 (3), 203-208

Lusk, C.H., Lusk, J.R. (1981)

Article Type: Paper

During December 1980, 121 adult New Zealand Dabchick (Podiceps rufopectus) and 14 young were counted on Rotoiti. Their distribution on the lake is discussed in relation to habitat and resources. Nesting habits and the effects of weather and recent habitat changes are also discussed. In spite of high nest failure, the population on Rotoiti appears to be stable.



The diet of the Australasian harrier (Circus approximans) in the Manawatu-Rangitikei Sand Country, New Zealand

Notornis, 28 (4), 241-254

Baker-Gabb, D.J. (1981)

Article Type: Paper

Of the 477 food items identified in the diet of the Australasian Harrier (Circus approximans), mammals (46%) were the main food. Birds and their eggs (41%) were the next most numerous food, and insects (8%) and fish and frogs (5%) were in about equal numbers. Live prey was numerically more important than carrion in all seasons and especially during summer. However, the biomass of carrion eaten annually was greater than that of live prey. Food items were taken according to their availability, and not according to preferences of the predator. The legal protection of the Australasian Harrier in New Zealand is recommended.



The external morphology and taxonomic status of the orange-fronted parakeet

Notornis, 28 (4), 292-300

Nixon, A.J. (1981)

Article Type: Paper

Size and shape differences between museum specimens of the Orange-fronted Parakeet (Cyanoramphus malherbi) and the Yellow-crowned Parakeet (C. auriceps) are investigated using discriminant function analysis. No significant differences were found between the two groups, and the plotted discriminant scores show very poor separation, whereas the technique distinguishes both groups from Red-crowned Parakeets. These results support the view that C. malherbi is a colour variant of C. auriceps.

The subfossil distribution of extinct New Zealand coots Fulica chathamensis subspp. (Aves: Rallidae)

Notornis, 28 (1), 1-9

Millener, P.R. (1981)

Article Type: Paper

The mainland form of the Extinct New Zealand Coot, Fulica chathamensis prisca (Hamilton), is recorded from 11 North Island and 21 South Island localities. Two published North Island records are shown to be invalid. It is noted that the Chatham Island form, Fulica c. chathamensis (Forbes), has been recorded from 18 named localities on Chatham Island and is also present in many collections for which no more detailed locality record than “Chatham Island (s) ” is available.