Two species of New Zealand parakeets or kākāriki (Cyanoramphus novaezelandiae and C. auriceps) are kept as cage birds in the United States and Britain. Protective legislation and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) prohibits any further export of these birds from New Zealand, but the overseas kākāriki continue to be bred and hybridised in captivity.
Stick insects and wētā pets
Three New Zealand species of stick insect, Acanthoxyla geisovii, A. inermis and Clitarchus hookeri, have become established in Britain. Stick insects are a curiosity in Britain as there are no native species there. A variety of exotic stick insects are sold in pet shops and occasionally escape, but the New Zealand species are the only ones tough enough to survive outside in the British winter. In Germany, wētā (Hemideina crassidens and H. thoracica) have been traded as pets.
Two native woodboring beetles, Euophryum rufum and E. confine, hardly noticed in New Zealand, have become notorious pests abroad. After reaching Britain (probably in exported timber) they made themselves known by attacking damp woodwork. These ‘New Zealand weevils’ are now among the commonest borer beetles in houses in Britain, and have spread to France, Scandinavia and Canada.
Some New Zealand native species went unnoticed until they spread abroad. For instance, a mealybug, Balanococcus diminutus, and a fungus, Kirramyces phormii, which both live on New Zealand flax, were first noticed on plants growing in Italy and Japan respectively and only later discovered in New Zealand. Similarly, a phytoplasma (a form of bacteria) known as Phytoplasma australiense was first identified in Australia when it spread there and began affecting papaya and other fruit. It was subsequently confirmed as having originated in New Zealand, where it has been found to be the cause of yellow-leaf disease in flax and ‘sudden decline’ in cabbage trees.
Not all successful invaders abroad are obscure natives at home. Just as European birds have become established in New Zealand, some native New Zealand birds have spread elsewhere. The southern black-backed gull (Larus dominicanus dominicanus) has become established in Australia within the last 50 years. New Zealand’s harrier hawk (Circus approximans) and silvereye (Zosterops lateralis lateralis) both became established in Tahiti after being liberated there by aviculturalists.