3. PEST CONTROL 3.1 POSSIBLE APPROACHES 3.1.1 Kill Trapping Humane kill trapping is one potential option for control of rats, possums, mustelids (stoats, weasels and ferrets), and cats. Trapping does not require toxin and provides employment. It does not require any special permission (e.g. from the Medical Officer of Health) which is typically associated with poison use. Trapping also enables options such as fur or skin recovery for possums and facilitates some types of research where data can be collected from trapped animals. Trapping also provides an accurate record of the number of captures per unit effort and where most animals are caught. This information can be useful for planning operations. The main disadvantage of trapping is the high cost. Factors which can contribute to the cost include the difficulty of carrying and setting up traps and trap boxes in steep and rugged terrain, and the amount of time required to cover a large area. There is also the possibility that some rats and possums which never come to the ground fail to encounter traps or that as densities of pests become low animals become harder to trap. Where trapping is used as the sole method of control over a long time, trap shyness (where animals avoid traps) can also occur. 3.1.2 Ground Based Toxin Ground based poison baiting i.e., where baits are delivered in bait stations or other bait delivery devices (such as bait bags or as a paste applied to tree trunks) is another approach. This method has the advantage that it provides employment and can still be used for fur or skin recovery for possums. In addition, the location of the toxic baits is known with certainty. The disadvantages are similar to those for trapping. If only one type of toxin (or method of presentation) is used for a long period, animals can become bait shy. In addition, different toxins are usually required to effectively control the suite of mammal predators. Furthermore, particular toxins have particular advantages and disadvantages that need to be taken into account. The method of presentation of the bait also depends on the target animal, although depending on the toxin, some non-target pests may be killed by secondary poisoning. The practical requirements of trapping and ground-based baiting are similar and include: • Lines marked out and/or cut through the forest can potentially increase the risk of spread of some plant and animal pest species (e.g. spreading kauri dieback or providing access for pest mammals). • Long, arduous days working in difficult terrain and vegetation, in all weather conditions; • Maintaining a good access road/track to trap line start points. 3.1.3 Aerial Toxin Aerial application of baits is most commonly associated with 1080. The Department of Conservation has undertaken aerial 1080 drops in the southern Coromandel before and this
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