The Department of Conservation says 1080 activists should apologise over what it says are misleading claims about the poison's effect on native birds.
The department has released a recording of birds in the Maruia forests near Reefton, after a claim that 1080 drops have made the area like a lifeless green desert.
Ian Gill, the department's public awareness manager, says he made the recording early on Tuesday morning in the Upper Pell Stream area.
Mr Gill says it shows anti-1080 campaigners need to get out of bed earlier to hear the birds and should apologise for their misleading claims.
Anti-1080 campaigner Laurie Collins, who made the claim, says he has years of experience in the forest and any suggestion of an apology is ridiculous.