Finding rooks is easy, eliminating them is not.
So the Otago Regional Council is asking people to let it know if they see them, but not to disturb them, as the council embarks on its annual rook control programme during the next couple of months.
Council compliance manager Martin King said rooks were extremely intelligent and inquisitive birds, which required a skilled approach to control.
Shooting at them, or trying to frighten them off, could result in scattering the population.
"Any attempt which disturbs them could mean we loose sight of them for good."
The rook was brought to New Zealand to control insect pests but, unfortunately, large flocks of them could inflict thousands of dollars worth of damage to Otago's grain and new grass crops.
Over the years, Otago's rook populations had been reduced to two - one in Middlemarch of about 60 birds, the other in South Otago of 40 birds, he said.
They were now quite stable but this relied upon people notifying the council of any sightings.
"This is essential to pinpointing where these birds are nesting, gathering or feeding in numbers."
There was no charge to the landowner for rook control.
People noticing rooks in Otago should contact the regional council on 0800-474-082.
