A study appears to support the theory that use of the controversial 1080 poison is not dramatically killing off birdlife.
The poison is used to eradicate possums, and has long been criticised for killing other wildlife as well.
But a University of Otago study of the native robin population north of Dunedin has given weight to the pro-1080 voice.
Nineteen birds were marked in the 1080 drop area, while 15 were marked outside of the drop zone.
And the results in the 1080 area surprised even the researcher.
"The 1080 drop did its job, it killed the possums and it also killed the rats. But it didn't kill the robins," said research supervisor, Associate Professor Ian Jamieson
"We had expected from past studies that maybe up to 20% might die, but all of them were alive."
The population increased in the 1080 area by 67%, compared with just 8% in the non-1080 area.
Jamieson says that is because possums and rats were killed off.
"It looks like there's two positives: Good survival rate for the native birds after 1080 drop, plus certainly a significant reduction in their predators."
1080 is dropped on 12% of the country's conservation land, and those who have supported its use are praising the study.
"I'm hoping that without increasing amounts of research like this, it will help put ordinary New Zealanders minds at ease," said Nicola Toki from Forest and Bird.
But anti-1080 campaigners aren't convinced.
"We're always a bit skeptical when they do these tests because they don't have someone from the opposition watching they're doing," said anti-1080 campaigner John Acker.
Researchers say they will repeat the study.