Taking to the air has proved the best way to tackle an avian pest that can significantly harm farm production.
Last week Waikato Regional Council contractors used an applicator dangling from a helicopter to place poison in five rook nests at Lake Te Ko Utu Park in Cambridge.
Rooks were originally introduced to New Zealand to control grass grub but are now classified as a pest under the council's regional pest management plan.
"They are a classified as a production threat as they feed on newly sown crops, especially the likes of cereals, peas and maize, and uproot young plants to get at the seed," says pest animals biosecurity officer Paul Quinn.
"They also damage pasture searching for grubs and interfere with silage by ripping up the plastic wrap."