Exotic Animals - Herbivores
The Feral Horse - Equus Caballus
Feral horses have been present in the Northern Territory since early settlement. In fact, the first major influx of horses into Australia was the importation of the Timor Pony at the Port Essington on the Coburg Peninsula in 1838-1849. Aerial surveys indicate that there are about 265,000 feral horses in the Northern Territory. Presently, major concentrations occur to the west of Alice Springs, in the Gulf region, in the Victoria River District and to the south of Darwin extending as far as Katherine. Feral horses also occur on Vanderlin Island in the Sir Edward Pellew Island Group and on Bathurst and Melville Islands. A small population of Timor ponies still runs wild on the Coburg Peninsula.
Feral horses are common in tropical grasslands and on semi-arid plains which offer the best forage, but are also found in hilly range habitat. Feral horses often retreat to higher relief or heavily wooded habitats to escape drought and/or mustering activities.
The economic impact which feral horses have on pastoralism is poorly quantified but likely to be significant. High dietary overlap indicates that the potential for competition between feral horses and cattle for food is high. Horses compete with stock for water which may be a crucial factor during drought. Horses also foul water and damage fences and troughs
It is clear that feral horses can cause serious environmental damage. Correlative data collected near Alice Springs indicate that feral horses accelerate gully erosion, foul water holes and natural springs and denude large areas of native vegetation. They may also displace native herbivores like kangaroos by removing food and shelter. Horses also promote the spread of weeds.
The Parks and Wildlife Service implements control of feral horses in most national parks which it manages. Currently there is a major horse control programme in the Victoria River District which has been declared a pest control area. The main methods of controlling feral horses are capture by mustering, trapping and shooting. All have been used in the Northern Territory.
Mustering is effective and has the additional advantage that some costs can be recouped through the sale of horses. The effectiveness of mustering campaigns can be improved substantially by using helicopters or light aircraft to spot horses. Radio-telemetered Judas horses can be used to locate groups of horses which are difficult to locate using other methods.
Water traps can be used effectively to catch horses in arid areas under dry conditions as horses need to drink regularly. Where feral horses cannot be caught or where no viable market exists for captured feral horses, shooting is the only available control alternative. Ground shooting can be effective on islands or in areas where horses are forced to visit water points.
It is labour intensive and impractical in rugged habitats where large-scale control is required. Ground shooting is not recommended when mobs larger than two horses are concerned because of animal welfare considerations. Helicopter shooting by trained personnel enables coverage of large areas and inaccessible country. It is the only practical way of achieving quick, humane, large-scale population reduction.
