Vertebrate pests in cropping systems

Mice during a mouse plague.

Although not often immediately thought of when 'crop pest' is mentioned, vertebrate animals (birds, mice, pigs, rabbits, wild dogs and kangaroos) can be a major problem in certain field cropping situations, with the potential to cause major damage to crops or property. Whether an animal becomes a pest can also be influenced by environmental conditions, for example drought can force animals into cropping areas or excellent seasonal conditions can promote breeding cycles.

In some cases, native animals can become pests of crops or pose a threat to humans. In these situations, Queensland's Nature Conservation Act (1992) allows for the application of a damage mitigation permit. This permit is required for both capture and removal, and culling activities.

Birds

Birds can be a major pest and their roosting and nesting sites can cause health concerns. Although a range of management options is available, a determined flock can make a particular crop unviable in some areas.

Problem birds and crops they damage

Non-lethal techniques for bird management include:

• scaring devices
• chemical repellents
• habitat manipulation
• decoy food sources
• exclusion netting.

Lethal methods of control involve shooting (directly reduce numbers through killing, or as a scaring or dispersal strategy), trapping and poisoning. Lethal methods are often labour intensive, opportunistic and may be of limited value in an overall management plan.

• reducing cockatoo damage to crops (DPI Victoria)
• reducing cockatoo damage to stored fodder, ripening crops and feedlots (DPI Victoria)
• bird management in grain storage facilities (CSIRO, under 'Pests of stored grain').

A damage mitigation permit is required for relocating or culling native birds.

Mice

The house mouse (Mus domesticus) can cause high levels of damage in crops and storage areas, as well as damage electrical equipment. Generally mice numbers are low, but plagues can occur when seasonal conditions are favourable. Mice plagues can also pose health risks in buildings.

Find out more information about the house mouse.

Pigs

Feral pigs (Sus scrofa) can cause major problems in cropping systems. They can be highly destructive, trampling and uprooting crops, spreading weeds and severely damaging irrigation systems, fences and other equipment. They also have the potential to transmit disease.

Find out more information about feral pigs.

Other animals

Rabbits (Oryctolagus cuniculus) can cause major soil erosion but are more of a problem in grazing than cropping areas as cultivation and other machinery operations tend to disrupt their burrows. Find out more information about rabbits.

Wild dogs (Canis familiaris) are primarily a problem on properties with livestock or working animals. As well as killing or injuring other animals, wild dogs can pose a health risk to humans and cattle. Find out more information about wild dogs.

Kangaroos can also cause problems in some areas, damaging fencing as well as competing with livestock for pasture. A damage mitigation permit is required for relocating or culling native animals.

Public health issues

Certain vertebrate pests also bring the risk of disease to humans as well as livestock or working animals.

Some bird pests carry potential health risks, particularly those that nest in buildings and storage areas where contamination from bird faeces can occur. Mice can carry a number of diseases, including salmonella. Some crops for human consumption have hygiene requirements. Mungbeans, for example, must not be contaminated by mice or birds.

Zoonoses are diseases that can spread from animals to humans. Wild dogs pose a hydatid tapeworm risk, which can give rise to hydatid disease in both cattle and humans. Feral pigs can transmit leptospirosis, brucellosis, and Q-fever, and have the potential to host diseases such as foot-and-mouth disease.