It’s breeding season for rooks, which means it is more likely you will see this unwanted organism. If you do, report your sightings to the local regional council but don’t go near the birds.
Rooks are intelligent and extremely wary of anything new or unusual. If they become suspicious, they will move to a new location, which can impede ongoing efforts to eradicate the species in New Zealand.
These large birds are a serious agricultural pest because of the damage they can do to crops and pasture, especially when present in large numbers. In New Zealand, they occur in east coast regions of the North Island, some inland areas of the Waikato and in smaller numbers in Canterbury. Their numbers are coming down, after years of control effort, but continued vigilance and control is needed if the goal of eradication is to be achieved.
Regional councils in the affected areas monitor rook populations to keep track of the numbers and distribution. Control methods must be carefully planned and carried out by biosecurity experts. Rooks scare so easily that the control (usually poisoning) needs to be carefully targeted and done right first time. That is why councils are advising land owners and occupiers to report sightings without taking action themselves.
Rooks congregate during breeding season, so can be more obvious. Signs to look for:
- Direct sightings: recognisable for their glossy black plumage, which can have a purplish tinge, and their distinctive sturdy pale-coloured beaks. They are also sociable birds, more likely to flock together than be solitary
- Sound: they call to each other with a harsh ‘kaah’ or ‘caw’ sound
- Rookeries: the breeding colonies, known as rookeries, are established in tall single trees, usually pines or eucalyptus. The large twiggy nests are distinctive.
See more about rooks on our culprit page.
To report a sighting, contact your local regional council.