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Westland petrels and hoki fishery waste: opportunistic use of a readily available resource?

Notornis, 49 (3), 139-144

A.N.D. Freeman; K.-J. Wilson (2002)

Article Type: Paper

The importance of fisheries waste in the diet of Westland petrels (Procellaria westlandica) was assessed using 3 different techniques. Dietary studies showed that during the hoki (Macruronus novaezelandiae) fishing season (mid June – early September), fish waste formed c. 63% of the solid food brought back to the colony and fed to chicks. After the hoki season, fisheries waste contributed only c. 25% to the diet. A survey of Westland petrels at sea found that, although vessels fishing for hoki influence the petrels’ distribution, only a small proportion of the population appears to use this food resource at any one time. Satellite tracking showed that, on average, birds spent 1/3rd of each foraging trip near vessels, but they foraged over much wider areas than those occupied by the fishing fleets. Although fishery waste now forms a substantial component of the Westland petrel’s diet, the situation suggests opportunistic use of a readily available resource, rather than dependence.

Pigeon bath-time

Southern Bird, 9 (Mar), 7-7

J. Wilson (2002)

Article Type: Article

History and causes of the extirpation of the providence petrel (Pterodroma solandri) on Norfolk Island

Notornis, 49 (4), 246-258

D.G. Medway (2002)

Article Type: Paper

The population of providence petrels (Pterodroma solandri) that nested on Norfolk Island at the time of 1st European settlement of that island in 1788 was probably >1 million pairs. Available evidence indicates that Europeans harvested many more providence petrels in the years immediately after settlement than previously believed. About 1,000,000 providence petrels, adults and young, were harvested in the 4 breeding seasons from 1790 to 1793 alone. Despite these enormous losses, many providence petrels were apparently still nesting on Norfolk Island in 1795 when they are last mentioned in documents from the island. However, any breeding population that may have survived there until 1814 when Norfolk Island was abandoned temporarily was probably exterminated by the combined activities of introduced cats and pigs which had become very numerous by the time the island was re-occupied in 1825.

Survival of breeding Finsch’s oystercatchers (Haematopus finschi) on farmland in Canterbury, New Zealand

Notornis, 49 (4), 233-240

P.M. Sagar; R.J. Barker; D. Geddes (2002)

Article Type: Paper

We investigated the annual survival of Finsch’s oystercatchers (Haematopus finschi) breeding on farmland in mid-Canterbury, New Zealand. Annual survival from 1987 to 2000 averaged 0.892, with evidence of a small amount of variation in survival rates through time (estimated SD = 0.034). We found no indication that survival rates differed between males and females. However, recapture probabilities showed that males had stronger fidelity to breeding territories than did females. These results are similar to those reported from populations of H. ostralegus in Europe. Because oystercatchers are long-lived, the survival rate of adults is the key component in determining population size. Intensification of agriculture on the breeding grounds and disruption to coastal feeding grounds may reverse the trend for population increase in this species. Consequently, the survival rate presented here provides a basis for predicting future population trends.

Twitchathon 2002

Southern Bird, 12 (Dec), 5-5

S. Saville (2002)

Article Type: Article

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