Rooks, part of the crow family, are large birds with glossy, purplish-black feathers. They were introduced into Aotearoa New Zealand between 1862 and 1873 to control insect pests, but like many other introduced species, their populations flourished and spread in some areas.

These intelligent birds can form large flocks (called parliaments) and can damage Otago's crops, pastures, and invertebrate communities through predation on earthworms, grass grubs, beetles, flies, moths, spiders, and other invertebrates. Rooks are attracted to recently cultivated paddocks and will feed on newly sown crops, causing significant damage.

In Otago, historical control efforts have reduced rook numbers from several hundred at their peak, to a handful of individuals today. No chicks have been reported in the last few years, meaning the rook population may now be non-breeding. We are continuing to carry out monitoring and surveillance for any remaining individuals. Rooks have previously been spotted in Māniatoto / Maniototo, Strath Taieri, Middlemarch, Macraes, and South Otago around Clinton and Clydevale.

• Size: Rooks are large birds, with an adult wingspan of 81–99 centimetres and weighing 280–340 grams. 

• Appearance: A purplish-black bird with a prominent, powerful bill. As they mature, they develop a greyish-white patch of scaly skin around the base of their pale beak. 

• Signs: During breeding (August–January), all birds live in rookeries (large communal colonies), often coming back to sites they’ve used in previous breeding seasons. Rooks travel up to 20 kilometres daily looking for food, from either rookeries or communal winter roosts.  

• Similar species: Magpies, blackbirds and starlings can appear similar; however, rooks can be distinguished by their large size, pronounced beak and distinctive ‘kaah’ call. 

• Habitat: Rooks in Aotearoa New Zealand typically inhabit open habitats like pastures, croplands and orchards, nesting in rookeries in tall trees like eucalyptus, pine, and macrocarpa. They are most concentrated in areas with suitable nesting trees and extensive field crops. 

August through till January when the birds are breeding and nesting in rookeries.

To get rid of the small, localised populations in Otago, rooks are in the eradication programme of the Otago Regional Pest Management Plan (2019–2029). The goal is to reduce the number of rooks in Otago to zero over the next 10 years, to prevent negative effects on economic wellbeing and the environment.

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 500 metres of any tree containing a rookery

• damage, disturb or interfere in any way with a rookery.

This rule prevents humans disturbing rooks and hindering control. The birds are wary, disperse easily and require a settled environment for successful control.

orc.govt.nz/rooks