During the first 20 years of organised European colonisation the main motive for the introduction of animals and birds was to establish a plentiful food supply since the New Zealand fauna provided little food and there was little land, except in Canterbury, immediately suitable for the growing of crops. With the advent of the 1860s the settlements had become sufficiently established for the colonists to turn their attention to other matters and new motives for acclimatisation appeared. For the most part the colonists came from a country where the taking of deer, grouse, pheasants, hares, partridges, rabbits, and salmon was the prerogative of a small privileged class to a country free of such restrictions but lacking game mammals and sporting freshwater fish and with few species of wildfowl. They quickly set about altering this situation. Further incentives for acclimatisation came to the fore and remained the main features of the majority of introductions and liberations until the first decade of this century when a new attitude towards introductions and their potential effects on native flora and fauna began to make itself felt.

A number of birds, including many which today are taken for granted–thrushes, blackbirds, starlings, sparrows, finches, yellowhammers, redpolls and skylarks–as well as others which did not become established–nightingales, woodlark, black cap, and titmouse–were introduced for sentimental reasons. Several animals and most fish were introduced for sport and food–rabbit, hare, deer, black swan, mallard duck, California and brown quail, pheasant, and brown and rainbow trout. Chamois, thar, wapiti, Canada goose, and chukor were all later importations. The opossum was introduced for the main purpose of establishing a fur industry. Some animals, for example, stoat, ferret, weasel, introduced as biological controls (i.e., to control other animals) have in their turn become pests. A few animals, such as wallaby and kookaburra, appear to have been introduced purely as curiosities.