Mynas are not a pest in NZ.

Common mynas don't get a lot of love outside of their native range, and New Zealand is no exception.

Them being called 'pests' is common, particularly in Australia, where they are completely unwelcome and their eradication in the near future is highly desired.

I don't know much about what mynas do in Australia. There, they are mainly accused of competition and aggression towards native birds, and are also called a human health risk (which I doubt). Given the fact that Australia's climate is in favour of the spread of mynas (unlike most of New Zealand), and the fact that Australia's avifauna is very different from NZ's, and the fact that the forests of Australia are different from NZ's, mynas very well could be an actual ecological pest in Australia.

In New Zealand, though? In regards to ecological impacts, at least, I'm afraid not.

The only evidence that I have found regarding a major impact that mynas have on other bird species in NZ is in Ell's Encouraging Birds in the New Zealand Garden (1981), in a part about starlings which reads, 'An aggressive bird held in check in the northern part of New Zealand by its cousin the myna'. Even this statement, however, seems to be based on anecdotes.

The only case in which I consider it reasonable to consider mynas a pest in NZ is when they have been seen near the nesting sites of New Zealand fairy terns; they have been shot because of this. Mynas destroy the eggs and chicks of other birds, and those of the fairy tern are unlikely to be exceptions. Given how small the NZFT population is, I can understand that having mynas in the vicinity of where they nest is not a risk worth taking.

As for other native birds, mynas don't usually breed or reside in NZ forests, which means that most native birds are safe from them. The natives that I imagine would be most vulnerable to having their eggs and chicks destroyed by mynas are banded, North Island NZ, and black-fronted dotterels, and pipits, as they are all small ground-nesters, but I haven't found anything regarding whether or not mynas have ever been seen destroying the eggs and chicks of these species. I imagine that native forest birds which would be effected on a small scale would be silvereyes and grey warblers that nest in gardens; these would be easy targets for mynas, but mynas destroying the eggs and chicks of either of these species in gardens has a negligible effect on the populations of both, as most of them nest in forests. I also imagine that if mynas tried to destroy the eggs or chicks of kingfishers that have their nesting sites in rural areas, the kingfishers would kill them, so they're in no danger.

In conclusion, there's no good reason to consider mynas a major ecological pest in New Zealand, and therefore, no good reason to eradicate them from the country.

It would be nice if facts such as these could be more widely known and understood, but given the fact that 'introduced = bad' comes naturally to most kiwis, I don't think that that will happen any time soon.