Around 700,000 hectares of land were targeted in last year's 1080 aerial drop, mostly in the South Island.
While it appears to have won the battle this time, Department of Conservation (DOC) workers aren't certain they'll win the war.
Pollen glows above the beech trees, and come autumn, the forest giants will be producing another bonanza of seeds for rats, mice and stoats.
DOC says helicopter-borne 1080 drops killed of more than 90 percent of rats and stoats last winter; now it looks like they'll have to do it again this winter.
Pest numbers explode in a heavy seed or mast year, but when the seeds run out, the rats and stoats start on the birds.
Mast years don't happen every year, but the amount of pollen in the air indicates another one is on the way.
But not everyone agrees with carpet bombing the bush with 1080. Peter Salters has been hunting for years and says there has been a huge decline in native birds.
"They may blame that on predators, but when there is a poison drop and keas and moreporks almost disappear virtually overnight, you can't blame that on predators."
But it's a battle DOC says it's losing in the long run, and with more beech trees expected to flower next year, it's likely another 1080 dump will go ahead regardless of the by-kill.