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Reducing cockatoo damage to stored fodder, ripening crops and feedlots | LC0011 |
Ian Temby, Flora and Fauna Branch
September, 2003 |  |
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This Landcare Note discusses options available for damage control
Introduction
Long-billed Corellas, Sulphur-crested Cockatoos and Galahs (referred to collectively as ‘cockatoos’ and illustrated in Figure 1) are well known for damaging germinating cereal crops. They can also cause damage to:
- ripening crops;
- feedlots;
- feed trails and stubbles;
- hay and straw bales;
- silage and grain covers.
In some cases, these problems are merely a nuisance; in others, serious damage can be caused. Many of the damage control measures suggested here can be used to deter other bird species.
Figure 1
1. Long-billed Corella Cacatua tenuirostris
2. Sulphur-crested Cockatoo Cacatua galerita
3. Galah Cacatua roseicapilla
Why do cockatoos cause damage?
Cockatoos cause damage by eating and by chewing non-food items. Chewing maintains their beaks at the correct length and condition. Almost all problems caused by cockatoos relate to their eating or chewing behaviour. The severity of many cockatoo problems is due to the social nature of cockatoos - they do most things in flocks. Cockatoos always flock together to roost. At night the noisy roosting behaviour of cockatoos can be a problem for nearby residents. Day roosts, used sometimes for several hours between feeding bouts, are often used repeatedly. Day roosts may also be casual or short-term rest stops. Wherever cockatoos land either feeding or beak maintenance chewing usually occurs, and damage may be caused.
Specific problems
Feedlots
Cockatoos feed on and foul stock feed. Placing hoods over feed troughs, or erecting shade cloth screens on three sides and above the troughs may reduce cockatoo feeding. Cockatoos like to have a clear view around them when feeding and are wary of hoods and screens. The localised destruction of birds may also be necessary. Farmers should be aware that cockatoos are also attracted to feedlots to eat undigested grain from cattle droppings. Young cockatoos that have just left the nest use this grain as a food source at a time when little else is available. The grain in cattle droppings actually helps enhance the survival rates of cockatoos and assists in increasing their numbers.
Feed trails and stubble
Cockatoos are attracted to feed trails and stubble after the harvest and up to the autumn break. They consume grain intended for livestock, and their presence may inhibit feeding by young lambs. Limiting cockatoo access to grain at this time is very important. Having grain easily available just after young cockatoos leave the nest increases their chances of surviving and maturing. Without access to grain fewer young birds will survive leading to a decrease in the overall cockatoo population. Feed trails for stock should be placed late in the day when cockatoos are going to their roosts. Stock can then feed through the night undisturbed. Feed out just enough grain so there is little left the next morning. Feed smaller amounts more frequently; or keep birds away until the stock have finished. Wastage can be reduced by placing feed in bird-proof troughs.
Set harvesting machines to minimise the amount of grain left in stubbles after harvest. Collect chaff and grain for stock feed.
Hay and straw bales
Cockatoos can demolish hay bales when feeding on seed heads within the bales. Placing shade cloth or hessian on three sides of haystacks will reduce the area of damage to the outermost bales on the open side of the stack. Removable panels can be used, so that access to other sides of the stack is still possible. If damage is severe all four sides of the stack can be covered. Damage to round bales in paddocks can be reduced by the erection of temporary walls. Made of shade cloth or hessian the walls should encircle the bales at 2-2.5 m high. Shade cloth lasts longer than hessian and can be reused in later seasons.
Silage and grain covers
Cockatoos can perforate the covers on silage pits, letting in air and reducing the quality of the silage. Silage covers can be protected by erecting shade cloth or hessian walls at 2-2.5 m high around them. As with the hay bale walls, shade cloth lasts longer than hessian and can be reused in later seasons. Damage to grain covers generally occurs when birds are attracted to spilt grain on, or around, the covers. When care is taken to reduce grain spillage, or to remove spills immediately, grain cover damage is much less likely. If damage is still occurring visual screens of shade cloth or other material can be used. A combined scaring and shooting strategy, using bird hides, Bird Frite® cartridges, taped alarm calls and gas guns, may also be effective, and may enhance the effect of the visual barriers.
Ripening crops
Cockatoos attack the edges of a ripening crop. Edges occur at the perimeter of the crop and around trees, dams and bare or thin patches within the crop. Reducing the edges within the crop reduces the number of sites from which cockatoos can attack it. It is important to discourage the development of ‘feeding patterns’ at the crop site. The first few birds on the crop are the most important ones to deter. Their presence will attract other birds. The crop protection program should start with shooting. This establishes the link between loud noise and danger. Shoot from several hides near the birds' main approach routes. Bird hides can be made of hessian or other material. Vehicles can also be used as mobile hides and left near the crop. Shoot from these ‘approach route’ hides, but switch to other hides regularly.
Once the birds associate the hides with danger, pursue them by stealth. Try to get as close as possible to the birds before shooting at them. The birds will become very wary. At this point, the shooter should wear bright clothing and be as obvious as possible. The birds will associate the colour with danger. The same bright coloured clothing should be worn each time the crop is approached and by other people working around the crop. Scarecrows can also be used, dressed in the same bright colours. Move the scarecrows regularly.
Scare guns can be introduced at this stage. Set the guns to operate at long intervals, and only when birds are likely to be feeding in the crop, usually early and late in the day. Move the scare guns every two to three days. They may be more effective if hidden - use the bird hides. Keep scare guns out of sight when not in use. Reinforce the scaring with some shooting, and with the use of Bird Frite® cartridges. While the approach outlined above may sound unusual, it has been shown to be effective.
Farmers should also consider providing an alternative, low-cost food source such as rice hulls as a decoy and to enhance the scaring strategy. Decoy food should be at least 500 m away from the crop so that scaring activities do not disturb the birds at the decoy site. No control should be undertaken near the decoy, no matter how tempting this is. Decoy sites are more effective when they are close to the birds’ flight path and close to trees that can be used as perches or roost sites. Decoy model cockatoos in the feeding posture can be used to lure birds to the decoy feed site.
Legal controls
Sulphur-crested Cockatoos, Galahs and Long-billed Corellas are classified as “Unprotected Wildlife” under the Wildlife Act 1975.
Shooting and trapping and gassing are allowed under an Order in Council of the Wildlife Act 1975.
The Order states: “(1) The species of wildlife listed in paragraph (a) above, (Sulphur-crested Cockatoos, Galahs and Long-billed Corellas) may be taken or destroyed by-
(a) landowners or occupiers, their employees and members of their families; or (b) in the case of recreational reserves, members of committees of management-
only where serious damage is being done to trees, vineyards, orchards, recreational reserves or commercial crops… “(2) Persons specified in paragraph (1) may take or destroy these species by- (a) the use of firearms in accordance with the Firearms Act 1958; or (b) using trapping and gassing equipment approved by the Department of Natural Resources and Environment—only on the freehold or leasehold property on which the damage is occurring.”
Firearms must be registered and used in accordance with the Firearms Act 1996. The Act prohibits the use of firearms in a town or populous place or on a street, road, thoroughfare or place open to or used by the public. Shooters must be licensed.
Poisons
There are currently no chemicals registered for poisoning cockatoos, and poisoning of Long-billed Corellas, Sulphur-crested Cockatoos and Galahs (and all other native birds) is strictly illegal. Contamination of crops by poisons threatens export markets for all farmers.
Successful damage control programs
Not all of the damage control measures outlined in this note will be effective in all situations. Cockatoos are highly intelligent. However, a control program has great potential for success if it:
- is carefully planned;
- is based on an understanding of cockatoo behaviour;
- is varied frequently;
- reinforces scaring stimuli with some killing;
- integrates a number of different measures; and
- is persistent.
The role of bird destruction
There is no evidence to support the view that a substantial reduction in the general population of Long-billed Corellas, Sulphur-crested Cockatoos and Galahs in Victoria would be effective in controlling localised damage.
Control of specific flocks as part of a larger, integrated strategy with diverse, mutually-reinforcing bird damage control measures, may be appropriate where individuals have severe damage problems.
Several things need to be considered before killing birds:
- killing birds is pointless if it does not lead to a reduction in the damage being caused;
- killing birds should not be undertaken if it costs more than the damage being caused;
- killing birds is usually only a short-term measure, and is unlikely to have much impact on the overall population size or its ability to recover to former bumbers: its main aim is to affect behaviour by causing large flocks to disperse;
- some destruction methods bring people into close contact with cockatoos. These people risk catching the disease chlamydiosis (psittacosis) if they inhale feather dust. Protective measures should be taken.
Destruction of birds may result in a short-term change in behaviour. But this can also be achieved at less expense by other means, such as using decoy food, scaring, or making barriers to hide fodder.
Further information
- Contact the DSE Customer Service Centre on 136 186 for further information.
Services and equipment
Gas guns
E.E. Muir,
542 Footscray Road, FOOTSCRAY 3011
Ph (03) 9687 6836;
Rural hardware or farm machinery outlets
Bird Frite cartridges
Ask your local ammunition dealer. Cost: $75.00 (approx)/box of 25.
Trapping and gassing
Trapping and gassing teams may be provided by DSE on request to destroy cockatoos on your property. Contact the DSE Customer Service Centre on 136 186 for further information.
Taped Alarm Calls
E. Thomson
Ph (03) 9846 1173
Tapes and CDs of Sulphur-crested Cockatoo and Long-billed Corella calls available. $15.00, plus p&p.
Further reading
ENRC (1995) Report on Problems in Victoria Caused by Long-billed Corellas, Sulphur-crested Cockatoos and Galahs. Parliament of Victoria, Environment and Natural Resources Committee.
The advice provided in this publication is intended as a source of information only. Always read the label before using any of the products mentioned. The State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.
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