Connor Mills, of Balclutha School, asks :-
What is the rarest native animal in NZ?
Rod Hitchmough, a zoologist with the Department of Conservation's Biodiversity Recovery Unit in Wellington, responded.
Your question is a very good one, which many people are asking. Unfortunately we don't know enough about many of our rare types of wildlife to know for certain which is the rarest. There are several types of insects and other invertebrates which have only ever been seen once - we don't know for sure whether some of these still exist, or whether no-one has looked in the right place to find them again. For example, the snail Phrixgnathus transitans, which is found in eastern Northland is known only from one individual, despite experts having searched for it. The moth species Euxoa cerapachodes has not been seen for more than 50 years despite a number of attempts to find it.
Among the birds, which we do know a lot more about, the rarest native is the fairy tern, with perhaps 30 individuals. However, other subspecies of fairy tern occur in Australia and New Caledonia. The rarest species of bird found only in New Zealand is the kakapo, with 86 individuals known.
The species with the lowest numbers are not necessarily those at the highest risk of extinction. Those which are more common now, but are declining very rapidly are also of great concern. The orange-fronted parakeet population was reduced by more than 90 per cent in 1999-2001 when there was a rat plague in an important part of its habitat, and the rats preyed on the birds and their eggs. Some slow-swimming, deep-water octopus species have been reduced from being very common to the verge of extinction within a couple of years of deepwater fishing boats starting to use nets in their habitat.