Very interesting about the moose and brush tailed rock wallaby.
Do you know how any of New Zealand’s invasive species got there? For some species is is quite obvious why they’ve been introduced, such as deer and game bird for hunting purposes, but for other species it’s a lot less clear. I’d especially like to know the origins of the various Australian marsupials, tahr, chamois and hedgehogs.
There are four main reasons animals were introduced to New Zealand:
1) Accidental introductions, i.e. the rats and mice which came on board the ships, and most of the invertebrate species, which came along inside food stores or with farming stocks.
2) For hunting, because the intention for the new colony was for there to be no class system, with even the lowliest person being able to go hunt a deer or catch a salmon if he wanted. This is why all the deer were introduced, the tahr and chamois, the rabbits and hares, and the waterfowl and gamebirds, and the fish (trout, salmon, etc).
3) Biological control - this was very much in its infancy and for the most part extremely ill-considered. The mustelids (stoat, weasel, ferret) were introduced to try and control the rabbits and hares which had been introduced earlier. Hedgehogs and passerines were introduced to try and control insect pests - with all the native birds being hunted into oblivion, the European insect species were exploding into plagues all over the country. The Little Owl was introduced to try and control the introduced passerines after
they started building into huge numbers and causing crop losses. More recent biological control efforts have been better handled and involve host-specific invertebrates for trying to control plant pests such as gorse (introduced as a farm-hedging plant) or other insects (e.g. parasitic wasps).
4) Simply because they weren't here already. For vertebrates this is the primary reason they were introduced, although the majority of species failed to establish. The time when New Zealand was being settled was when Britain was starting colonies all over the world and a) wanted to make each colony as much like England as possible by introducing familiar animals, and b) had ready access to all sorts of animals from other colonies and wanted to spread them all around the world as well. So some of the above animals were introduced for two reasons - e.g. hedgehogs were introduced to try and control pests but also because they were familiar English animals which they wanted in the new country. But other species were for no reason other than "why not?" - amongst the species which became established are the wallabies, frogs, and a number of the birds like kookaburras, parrots, peafowl, etc. But there were literally hundreds of species of birds and mammals introduced into New Zealand which failed for one reason or another - there were monkeys, zebras, emus, quolls, kangaroos, etc etc.
Finally, one animal which falls outside any of the above reasons is the Brush-tailed Possum which was introduced to try and establish a fur trade.
