toxins

We used a long-term replicated before-after control-impact (BACI) sampling design to monitor the effect of aerial 1080 possum-control operations on common forest bird populations. Paired treatment and non- treatment sites in the Rolleston Range (East Coast, South Island) and Alexander Range (West Coast, South Island) were monitored once before 1080 treatment during winter 2012 and for three successive summers afterwards. Mammals (possums Trichosurus vulpecula, rats Rattus spp.

In poisoning operations, sublethal consumption of the toxin, can produce bait aversion. This decreases the effect of the poisoning and may create problems due to the presence of uneaten toxin in the environment. The use of new bait additives may prevent aversion development. Here I report the effects of two bait additives, corticosterone and mifepristone, in altering bait aversion development in rats exposed to the widely used poison, monofluoroacetate (1080). Corticosterone is a glucocorticoid hormone, released in response to stress.

Vertebrate pest control operations using toxic baits can have unintended consequences for nontarget species. some of which may themselves be pests. Learned avoidance behaviour (termed 'aversion') can be induced by sublethal dosing, which can arise when species with high and low susceptibilities to a toxin co- exist in the same area. In such cases the less-susceptible species (e.g., possums Trichosurus vulpecula) may be sublethally poisoned by control work targeting the more- susceptible species (e.g., rabbits Oryctolagus cuniculus).

Toxins, especially sodium monofluoroacetate (1080) and brodifacoum, are widely used throughout New Zealand for control of introduced mammals that are considered pests. This level of toxin use (not necessarily with these toxins) is unlikely to decline for at least 5-10 years. Ecological consequences derive both from mammal population reduction or eradication, and from using toxins as the control method.

Kea (Nestor notabilis), large parrots endemic to hill country areas of the South Island, New Zealand, are subject to anthropogenic lead (Pb) exposure in their environment. Between April 2006 and June 2009 kea were captured in various parts of their range and samples of their blood were taken for blood lead analysis. All kea (n = 88) had been exposed to lead, with a range in blood lead concentrations of 0.014 – 16.55 ìmol L^–1 (mean ± SE, 1.11 – 0.220 ìmol L^–1). A retrospective analysis of necropsy reports from 30 kea was also carried out.