pest control

A knowledge of the sensitivity of the brushtail possum (Trichosurus vulpecula) to 1080 poison is important as a basis for planning effective control campaigns. This study assesses the effects that experimental procedure may have on determining the LD50 of 1080 for brushtail possums and reports on the variation in sensitivity within and between different populations of the species in Australia, where it is indigenous. LD50s obtained ranged from 0.39–0.92 mg kg-1, with 95 % confidence limits of from 0.29–1.20 mg kg-1.

North Island robins (Petroica australis longipes) and tomtits (P. macrocephala toitoi) are at risk of being poisoned during pest control operations in New Zealand. Robins are deterred from feeding on diets containing primary repellents (e.g. blue colour, d-pulegone) and secondary repellents (e.g. illness-inducing materials such as anthraquinone, which induce taste aversions). We tested, with wild robins, primary and secondary repellents surface-coated onto dough baits, over 4 days on Tiritiri Matangi Island.

Dama wallabies (Macropus eugenii) are an introduced pest in New Zealand requiring control. Historically, sodium fluoroacetate (1080) has been used to control wallabies but there is increasing resistance to this method of pest control. Pen trials have shown that Feratox® cyanide pellets are an effective and humane toxin for use on dama wallabies. The aim of this study was to test the effectiveness of these cyanide pellets in field trials for controlling dama wallabies.

Introduced mammalian predators are a major threat to New Zealand’s wildlife, including bats. Controlling these predators using traps and poison baits can reduce their impact on bat populations. However, lesser short-tailed bats (Mystacina tuberculata) are potentially susceptible to toxins used for pest control in New Zealand forests because of their broad diet and habit of feeding on the ground. Therefore, the risk of secondary poisoning should always be assessed before new toxins are used in areas inhabited by lesser short-tailed bats.

In 2007 The Nature Conservancy (TNC) undertook an intensive ungulate control programme throughout three of its preserves on the Hawaiian islands of Maui and Moloka'i, with one aim being to reduce feral pig numbers to zero or near zero. The preserves were divided into manageable zones and over a 2 to 5 month period hunted from the ground with dogs in a series of up to four sweeps across the zones. More focussed hunting followed at sites with evidence of survivors. We used the data collected by the hunters to evaluate the efficacy of the control programme.

Productivity data on the New Zealand falcon (Falco novaeseelandiae) were collected from 87 nest sites in Kaingaroa pine plantation during three breeding seasons, 2003 to 2006. On average, 1.81 chicks were successfully fledged per nest, with young reared successfully at 71% of nests. Breeding occurred between August and March, with most eggs laid before December and most chicks fledged by February. Fifteen percent of nests were depredated, 9% contained eggs that failed to develop and 4% failed owing to forestry operations disturbing or destroying nests.

Investigations of nest predation are often limited by the researchers’ inability to identify nest predators accurately. I tested a chemical bait marker, Rhodamine B (RB), as an indicator of egg predation at artificial ground nests. In a pen trial, the presence of characteristic fluorescent bands in one or more facial vibrissae from all treatment animals confirmed the suitability of RB as a bait marker in the introduced European hedgehog (Erinaceus europaeus).