Pest birds

Rooks and Australian magpies are both aggressive birds known to raid the nests of native birds, destroy eggs and tip out fledglings.


Depending on your area of New Zealand you may encounter a series of different pest birds. Here we focus on rooks and Australian magpies. Check your local regional council if there are other pest birds in your area. 

The rook (Corvus frugilegus) is black, with a violet blue glossy sheen. It is approximately 50cm long and weighs 350–500 grams. Adult birds are typically crow-like in appearance, and can be distinguished from younger rooks by conspicuous greyish-white bare skin at the base of the beak. In juveniles this area is feathered in the first year, diminishing during the second year until just a few feathers remain at the base of the beak.

Magpies were introduced to New Zealand in the 1860s from Australia to control pastoral insect pests. Two sub-species were introduced, the whitebacked (Gymnorhina tibicen hypoleuca) and the black-backed (Gymnorhina tibicen tibicen) magpie. Crossbreeding has occurred and they are now considered one species. Both are black and white in colour.

Regional councils have primary responsibility for rook control in New Zealand. At the strategic level, policies and goals are set in each regional pest management strategy. These goals are then pursued via annual plans, which dictate when and where control and monitoring will be carried out.

Methods of control for rooks 

Rooks are intelligent birds so control efforts must be infrequent, professionally undertaken and effective.

Shooting makes for wary rooks, which will then tend to abandon existing rookeries causing the population to fragment into more and smaller rookeries further afield. Most regional pest management strategies prohibit shooting, or piecemeal poisoning attempts by occupiers, and this important aspect of rook management needs to be clearly communicated to the rural populace

Ground baiting 

Ground baiting is mostly carried out during summer when the ground is hard, earthworms (a favoured food) descend in the soil and become unavailable, and rooks congregate to scarce food sources such as harvested pea or cereal stubble fields. At this time, birds are still feeding around rookeries but are in moult and thus less mobile.

Please read 'Pest Rooks: Monitoring and Control' in the Library for further information in ground baiting.

Methods of control for magpies 

Trapping 

For welfare performance of animal traps go to https://www.bionet.nz/control/pests-under-management/performance-traps/

Many traps are commercially available, including Larsen traps, the Arcane™ magpie triptrap, letterbox traps and adapted possum cage traps. These are all live capture traps that allow other birds to be released unharmed.

The Larsen style trap is very popular. It is a double caged trap with a flap door held open by a false perch which, when triggered, falls down, releasing the flap and trapping the bird. A decoy magpie is placed in one side of the trap to attract others to it. Alternatively, you can bait traps with bread, mutton fat, mirrors or a miniature disco ball, anything to attract their attention. The Larsen trap is most effective during the breeding season ( July through summer), as magpies are particularly territorial at this time.

Shooting 

Random shooting of magpies is unlikely to achieve any significant control of the local population. For effective shooting, use a magpie distress recording. Sound files of distress calls can easily be found online.

Playing the recording of distressed magpies will attract magpies from up to one kilometre away. Use this method sparingly, as surviving birds quickly become ‘gun shy’ and wary of the distress call recording.

Camouflage the distress call player in an open area. The shooter should also be camouflaged and make good use of natural cover. Only shoot birds once they have landed – do not shoot them when they are in the air or roosting in trees. Use a .22 rifle with a sound moderator.

Poisoning 

Large populations of magpies can be successfully controlled using the narcotic poison alphachloralose. This product, when used in concentrations of 2.5 per cent or below, will anaesthetise birds rather than kill them. Comatose birds can then be collected and humanely killed. Non-target species can be revived by placing them in a warm dark place.

A poison license is not required to use alphachloralose if used in concentrations of 2.5 per cent or less. Several commercial baits are available with grain lures for other pest species. When targeting magpies use bread covered in alphachloralose paste. Pre-feeding is recommended. This gets the magpies used to the bread and gives you a chance to estimate how many birds are present in the area, so you can tailor the amount of alphachloralose required.

Alphachloralose paste is available from most rural supply stores.

Disclaimer: Any product names mentioned are not an endorsement nor are they a criticism of similar products not mentioned.

Legal requirements 

For a list of legal requirements check out the legal requirements page

Disclaimer

The information on this website is intended to provide information about pests and pest management in New Zealand. We've made every effort to make sure that the information set out in this website is accurate. If you have an update to the information listed here please contact us.