New Zealand plan to eradicate rats

[Catherine]

The arrival of humans in New Zealand brought pests such as rats. The rats have been responsible(at least partly) for the extinction or near extinction of New Zealand's unique bird species. The rat population is in the millions. There are also possums and stoats. There are a staggering number of pets that need to be removed to protect New Zealand's birds.

http://news.google.ca/news/url?sr=1&ct2=...t=1&at=dt0

The idea of saving the birds is good.  No one would argue with that. However it is a monumental task that would involve the slaughter of millions of animals. I am not sure that the rats couldn't reproduce faster than they could be killed off.

I don't know what they can do or should do. Killing millions of animals seems wrong, but if they don't act they will lose all their unique birds. If they do it wrong the rats will just keep multiplying and the killing will become a permanent thing.

We have created a real mess with this one. Many countries are struggling with invasive introduced species. I would hope they would find a way to stop rats from reproducing. That seems like a kinder more effective way. I don't even know if that is possible. If we don't find a kinder way massive culls might become common in a great many places.
Any thoughts on that.