The Fate of Birds and Selected Invertebrates during a 1080 Operation

An aerial 1080 poison operation for possums at Waipoua Forest in spring 1990 applied cereal pellets lured with cinnamon. Numbers of brown kiwi, moreporks, fernbirds, kokako and common diurnal birds were monitored before, during and after the operation, while small numbers of insects and kauri snails were tested for 1080 uptake. Of the birds only blackbird and tomtit showed possible declines after the poisoning. Although some kiwi had consumed non-toxic baits, no 1080 related deaths were detected following the poison operation. Low concentrations of 1080 were found in the insects, but none of the kauri snails had detectable levels of 1080. INTRODUCTION During aerial 1080 operations for possum control in the 1960's and 1970's there was sometimes high mortality of non-target species of birds. Trials to determine safer baits showed that screening out fragments and using a green dye with a cinnamon lure all helped to lower mortality for most common bird species (Harrison 1978, Spurr 1979, Warren 1984, Calder and Deuss 1985). The impact of 1080 on many species of animal however, including several in the previously unpoisoned Northland forests, remained uncertain. Thus, when a 1080 programme was planned for Waipoua in 1990 there was a need for some preliminary experimental work as well as monitoring before and after the poison operation. The area studied in shown in Figure 1. The concerns addressed at Waipoua included:1. Brown kiwi (Apteryx australis) : The omnivorous diet of kiwi could lead to birds consuming 1080 pellets. 2. Morepork or ruru (Ninox novaeseelandiae) : This species feeds largely on rodents (which feed on 1080 baits and obtain lethal doses) and invertebrates (some of which are attracted to baits). Moreporks could, therefore, obtain quantities of 1080 via their prey (Spurr 1991).