The first donkeys were brought to Australia in 1866. They were used widely as pack and draught animals until the early 1900’s when they were superseded by motorised transport. As transport improved donkeys were liberated and large populations built up. In the 1920’s and 1930’s large numbers of feral donkey populations were reported and by 1949 the donkey was sufficiently numerous to be declared a pest in Western Australia.

Adrienne Markey Donkey

Image by Adrienne Markey

The feral donkey is well-adapted to arid regions and is most abundant in the Kimberley pastoral district of Western Australia and the Victoria River area of the Northern Territory. Lower densities are found in the semi-arid regions and deserts of central and western Australia. Although absolute numbers are difficult to estimate, there are thought to be between 2 and 5 million feral donkeys in Australia.

Feral donkeys are both grazers and browsers and feed during the day on a wide variety of plants. They can subsist on coarser vegetation than horses and in the Kimberley region are attracted to perennial tussock grasslands. Large mobs of up to 500 animals congregate on residual sources of water and favoured grazing areas during the dry season. During the wet season they disperse in groups of less than 30 individuals to take advantage of the abundant growth.

Feral donkeys are seasonal breeders, with births occurring between September and February. Females reach sexual maturity in their second year and can produce one young per year under favourable conditions. In northern Australia more that 75 per cent of females breed annually. Annual population growth can approach 25 cent under good seasonal conditions or when recovering from a culling program. As a population recovers and higher densities are attained, females continue to breed but their capacity to rear their offspring declines. This decline is related to increasing competition for favoured forage species; females being ultimately unable to procure a diet sufficiently nutritious to meet the demands of lactation. Mortality of juveniles eventually increases to more than 60 per cent in the first six months of life, with less dramatic increases in mortality in adults. At this stage, population growth stalls and equilibrium with the food supply is established until disturbed by a shift in seasonal conditions or by culling.