Large parliaments (the name for a flock of rooks) of these birds can inflict thousands of dollars’ worth of damage to Otago's grain and new grass crops.

Rooks love to eat fields of cereals at all stages of growth as well as other seeds that have recently been sown. They also pick at stands of walnut trees.

Rooks were brought to New Zealand between 1862 and 1873 to control insect pests.

The goal is to reduce the number of rooks in Otago to zero over the next 10 years, to prevent negative effects on economic well-being and the environment.

There is only one rule for rooks in Otago. Unless you are under the instruction or supervision of an Authorised Person (for the purposes of our pest plan an authorised person is a warranted officer under the biosecurity act, for example one of our biosecurity officers), you cannot:

• Poison, capture or trap any rook
• Discharge any firearm at any rook
• Discharge any firearm at or within 500m of any tree containing a rookery
• Damage, disturb or interfere in any way with a rookery.

The purpose of this rule is to stop humans making the control of rooks difficult.

Rooks scare and spread out very easily and need a settled environment for successful control.     

Rooks are large birds with glossy, purplish-black feathers. They are part of the crow family, although we don’t have crows in New Zealand so if you see something that looks like a crow, it might be a rook.

They have a powerful beak with white-ish patches of skin around the base. They are a social bird and you can hear them coming by the distinctive sound of their ‘kaah’, and as they fly. They ‘caw’ to keep in contact with each other.

During breeding (August-January), all birds live in rookeries; they often come back to sites they’ve used in previous breeding seasons. Rooks travel up to 20km daily looking for food, from either rookeries or communal winter roosts. There are thought to be less than 40 rooks remaining in Otago.

ORC controls rooks from September to November each year. The success of this control programme relies on any rook sightings being reported to us so we can we can pinpoint where they are gathering, feeding and nesting in rookeries.

There is no charge to the landowner for rook control in Otago.

ORC control efforts have reduced rook numbers to around 40 rooks from thousands at its peak. No chicks have been reported in the last few years, meaning the rook population may now be non-breeding. Rooks have previously been spotted in Maniototo, Strath Taieri, Middlemarch, and South Otago around Clinton and Clydevale.

If you see rooks in Otago contact ORC 0800 474 082 or by emailing biosecurity@orc.govt.nz; in Southland: 0800 76 88 45 or email service@es.govt.nz