Why are Rooks a problem?
Rooks are declared a pest under the Hawke's Bay Regional Pest Management Strategy. They are the most destructive introduced birds known to our farming sector, due to the sheer numbers of birds in congregations that may range into the thousands. These birds can strip crops in a matter of days, and flocks of rooks foraging in paddocks for grass grub and worms damage paddocks.
During their breeding season, they build rookeries near houses or woolsheds and the noise from the rooks is intense and very unwelcome to any household.
Description and background
Rooks are a large bird approximately 50 cm in length (adult) with 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, which develops when the bird is at least one year old.
Rooks breed between September and mid October, when 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. From February to late August, individual groups form large mobs that move around the region looking for food and use a series of different roosting sites.
What we are doing
HBRC has set a Rook Eradication Zone with the objective of eradicating rooks north of State Highway 5. Control in this area is principally by helicopter and bait is applied by hand directly to each nest by an operator slung underneath.
The rook control programme operates during September and October each year. Our Biosecurity staff and contractors contact farmers with known rookeries beforehand to advise them that the programme is recommencing, and to assess any hazards or manage any farmer concerns about overflying stock or property. Each visit by the helicopter takes 5-20 minutes once a year.
What can you do?
The best thing to do is contact HBRC’s pest management team about grazing rooks, nests or rookeries. Our biosecurity team will discuss the problem and solutions, and ensure prompt action is taken.
Please avoid any individual control or scare tactics as that can move the rooks on and delay our ability to control them.