Welcome to the Hawke’s Bay Regional Council’s webpage about rooks.
On this page…
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Above: A rook |
Rooks have a glossy black plumage with a slightly purple tint and have a distinct harsh call “kaah” or “caw”. On the rooks forehead and throat area is a grayish/white piece of scaly skin, which extends from the base of the bill to the nostrils. This patch distinguishes the adult bird from the juvenile, as it does not develop until the bird is at least one year old. The adult rook is approximately 50 cm in length. The adult male will weigh 450-500 gm, a female about 400 -450gm and a 1-2 year old juvenile 350-450 gm.
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| Above: Nesting female rooks |
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Rooks are the most destructive introduced birds known to our farming sector, due to the shear numbers of birds in congregations and that may vary from the Hundreds into the Thousands, these birds are able to strip crops in a matter of days. The flocks of rooks foraging of paddocks for grass grub and worms can leave paddocks looking like mobs of pigs have been through them.
During their breeding season rookeries are built near houses or woolsheds and the noise from the rooks is intense and very unwelcome to any household.
Breeding
Rooks breed between September and Mid October, the male and female share the incubation duties. Between 2 to 6 eggs are laid. During the breeding season only one established rookery is used and the same group of birds use the same rookery every year. If you have a breeding rookery on your property contact the council.
Non Breeding Season
From February to late August, individual groups form large mobs that move around the region looking for food. At this time they become very transient and use a series of different roosting sites.
Recommended control or scare tactics are:
Scarecrows – These can be effective if used correctly. Move the scarecrow around so the rooks do not become accustomed to it.
Decoy - The most effective is tying a dead rook or alternatively a magpie between two standards in a “crucified stance”. Warning: ensure all standards etc are removed before harvesting the crop.
Bright Objects - Plastic shopping bags and strips of bright polythene can be tied onto fence lines so they flap in the wind; alternatively, standards in an open field with plastic bags tied onto them offer some form of protection.
Gas Operated Bangers – This is a good method of deterring rooks from returning to a crop.
Contractor - The Regional Council uses a contractor who is able to poison ground-feeding rooks. For more information about this service contact the Regional Council 0800 108 838.
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Strategy Objective
- Rook Eradication Zone – The Council’s objective is to eradicate rooks north of State Highway 5. Control in this area is principally undertaken by using a helicopter for aerial rook control. Bait is applied by hand directly to each nest by an operator slung underneath a helicopter.
- Currently the aerial rook control program has been able to be bought below State Highway 5, where the whole entire area was treated by helicopter for the first time.
- Identifying and notifying the Regional Council biosecurity advisory team about Nesting Rookeries on your property is an important step towards helping us control rooks.
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Above: Aerial rook control in action. |
The rook was brought to New Zealand from Britain between 1862 and 1874 to help control insects and to remind settlers of home. The rooks belong to the family Corvidae which includes crows and jays and are among the more intelligent birds. Rooks like areas where there are walnut trees and agricultural crops, especially cereals. They avoid the bush and forested areas so are no real threat to our native or endemic birds. They prefer to eat insects, earthworms and walnuts but when these become scarce the birds may gather in large flocks and eat maize, wheat, barley, peas or beans. In 1971 rooks were declared an agricultural pest in the Hawke’s Bay and something like 35,000 thousand were shot or poisoned , possibly about half the known population at that time.