About Bird Control

The term 'bird control' is applied to the various methods used to prevent pest birds (such as pigeons) from landing, roosting and nesting. There are a range of techniques - some are fatal to birds, but many are harmless deterrents designed to simply drive them away.

Managing the population and nesting sites of pest birds is important in our communities. One of the main reasons for this is that the birds can cause health problems and transmit diseases through their faeces. Diseases transmitted in this way include histoplasmosis (affecting the lungs), cryptococcosis (affecting the heart or brain), and psittacosis (affecting lungs, liver, blood and more); all are extremely serious and can be fatal in some cases.

Pest birds are also a significant problem in civil engineering and town planning terms. Bird droppings can cause damage to buildings and equipment, as can nesting. There are also problems associated with large populations of birds flocking around airports, as birds striking aircraft can cause serious damage and occasionally accidents.

Techniques used in bird control include both chemical and physical deterrents and treatments. The use of avicides - chemicals designed to terminate birds - is restricted in many countries, but they are still used in some places. Non-fatal chemicals are also in use - some bad-tasting formulas are sprayed onto grass to prevent geese from eating it, for example. The use of non-fatal chemicals is generally permitted in most places.

Bird netting has nothing to do with the capture of birds. It refers to the practice of erecting netting over crops, or putting it underneath structures like bridges, to prevent birds from landing. It also ensures they can't get close enough to fruit and vegetables to snatch them from mid-air, and nets can also be put over ponds to protect fish and other aquatic life from predatory species like herons.

Bird frighteners come in many shapes and sizes and rely on different tricks to frighten pests away. Balloons with brightly painted eyes, specialized kites and reflective material can all be employed in this way. The movement of the frightener startles the birds, driving them away. In the case of kites, the hovering motion tricks birds into believing a bird of prey is nearby, causing them to fly away to safety.

As well as visual tricks, pest controllers and farmers employ sonic techniques to startle birds. Ultrasonic devices emit a high frequency noise said to deter birds, although some ornithologists dispute how effective they are.Another piece of audio trickery is to play distress calls of birds, or the hunting noises of predators, through loudspeakers. The random nature of these sounds is crucial, as birds will get used to a sound if it is repeated often enough and does not vary in pitch.

Other audio techniques are a little more pyrotechnic. Propane gas cannons produce loud bangs designed to startle birds away. The drawback is that birds can get used to the sound, whereas people living nearby do not and become quite irritated by it.

Cartridge frighteners use a similar idea but fire screaming shells or other whistling projectiles. They are used near airports to direct flocks of birds away from aircraft; however, there is always the risk of birds growing accustomed to the sound.

Traditional techniques are still very popular too. The reliable scarecrow is still seen in fields, although his effectiveness is sometimes called into doubt when birds perch on his shoulders. Model birds of prey, or even dead birds, can have an effect on pests as well.

Nature's way is sometimes relied on, too, with birds of prey and even cats being used as pest control, particularly in built up areas where the use of sonic deterrents would be unwise.

Prevention is often better than cure, so the final method to consider is controlling the population of pest birds by restricting their food supply or preventing them from breeding. This is much harder in rural areas, but in cities it can be helped by encouraging the general public not to feed pigeons. Some cities also build large roosts for pigeons: when the birds lay eggs they are immediately collected and destroyed, helping to reduce the population.

There are continual developments in bird control technology, but at the moment nothing is guaranteed to be 100% effective - not even the trusty cat. For now, the battle with pest birds goes on.