Rooks
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Rooks (Corvus frugilegus) are destructive pest birds which threaten Waikato farms. Environment Waikato controls rooks to protect agricultural production. Rook numbers are low in the Waikato at the moment (May 2009), and although we would like to eradicate them, it is not feasible due to reinvasion from neighbouring regions. Find out more about rooks, their control and what to do if you spot a rook.
Why rooks are a pest
Rooks:
- feed on and damage newly sown crops, particularly cereals, ripening lentils, walnuts, acorns, pumpkin seeds, and occasionally potatoes and fruit. In large numbers, they can devastate emerging crops, necessitating re-sowing.
- damage pasture by tearing it up in search for seeds and grubs and damage silage covers.
About rooks
Rooks are members of the same family as crows and ravens. They are native to Great Britain and Europe and were introduced to New Zealand in the 1860s to control insect pests.
Their numbers in our region are reducing. Find out the Regional Pest Management Strategy 2008-13 objective for rooks.
Rookeries (nesting sites) could be anywhere in the region, but are likely to be close to areas already identified and targeted for control. These areas are (as at April 2009):
- Meremere
- Miranda
- Maramarua
- Ngatea
- Gordonton
- Hamilton West/Templeview
- Matamata/Okoroire/Hinuera
- Mangakino/Whakamaru
- Kereone/Walton
- Cambridge/Fencourt
Identifying rooks
Many people confuse rooks with crows. However, there are no crows in New Zealand.
| plumage |
glossy black with a violet-blue tint |
| size |
adult birds are 30-50 cm long |
| distinguishing feature/s |
a greyish piece of skin at the base of the bill (from one year of age) |
| call |
several different calls, but most common is a harsh ’kaah’ |
| breeding |
- form conspicuous nesting sites (rookeries) of four to 100 birds
- often nest in pine and eucalyptus trees
- lay two to six pale bluish-green eggs covered with grey blotches and spots from September to mid-October
- on average one to two chicks survive from each nest per year
|
Which ‘black’ bird?
|
Rook |
Magpie |
Blackbird |
|
 |
 |
 |
| Control status (as prescribed by the Regional Pest Management Strategy) |
Pest, controlled by Environment Waikato. |
Pest, controlled by landowners and community groups with support from Environment Waikato. |
Not considered a pest. |
| Plumage |
Glossy black with a violet-blue tint, white face. |
Black or grey with white to grey hind neck and/or back. |
Black (male) or dark brown (female). |
| Size |
30-50 cm long |
35-45 cm long |
up to 25 cm long |
| Common call/s |
‘Kaah’ |
‘Quardle oodle ardle wardle doodle’ |
Tuneful call. Harsh ‘tchink’ if disturbed. |
| Distinguishing feature/s |
Greyish skin flap on adult birds reaching from bill to nostrils.
Dark-grey bill. |
White marking on wings and tail.
Whitish bill with black tip. |
Smaller bird.
Bright yellow bill (male), brown bill (female). |
Control
Environment Waikato monitors rooks and controls them by nest poisoning. People should not try to control rooks themselves, as they are likely to spread further. This can make professional control more difficult. Landowners may not carry out rook control on their properties and it is illegal to keep a rook as a pet.
Reporting rooks
If you see a rook, please let Environment Waikato know by:
Use our rook sighting form, or phone 0800 BIOSECURITY (0800 246 732).
If reporting rooks over the phone, please try to provide the following information:
- date and time sighted
- location
- was it a lone rook – flying, nesting, feeding?
- was it a flock of rooks – roosting, nesting, feeding or otherwise?
Thank you for helping to rid the Waikato region of rooks.