Control methods (FAQ)

Why can’t the brumbies of Kosciuszko National Park be managed in the same ways as the wild horses of Assateague Island, USA?

If horses are shot and their carcasses left on the ground, won’t that feed feral pigs and increase the pig population?

If horses are shot, will visitors to Kosciuszko National Park see dead horses on the ground?

If horses are shot and their carcasses left on the ground, won’t that feed feral pigs and increase the pig population?

Does grazing by feral horses reduce the risk of bush fires in Kosciuszko National Park?

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Why can’t the brumbies of Kosciuszko National Park be managed in the same ways as the wild horses of Assateague Island, USA?

Assateague Island, on the east coast of the United States, supports a stable population of about 230 feral horses. It is often quoted as an example that Australia should follow e.g. by the Australian Brumby Alliance[1].

The 80 horses – roughly 40 mares – in the northern section of the island (Maryland) are managed by a contraceptive darting program and the 150 horses in the southern section (Virginia) are managed by annual round-up and sale.

The challenges of horse management on Assateague Island and in Kosciuszko National Park are vastly different in scale:

1. the total Assateague horse population is around 230 horses, a fraction of the thousands of feral horses in Kosciuszko;
2. the land area of the island is 63 sq km, compared to Kosciuszko’s 6,900 sq km
3. Assateague Island is a sand-barrier island and almost flat (sea level to 14 metres), compared to Kosciuszko’s range of 2000 vertical metres [2]  [3].

The above three factors mean that management techniques suitable for Assateague will not scale up enough to be effective in Kosciuszko National Park. Some reasons, in detail:

1. Contraceptive darting requires darts to be delivered more than once. It is necessary for the people delivering the darts to recognise each mare so that mares are not accidentally darted more often than required, and that no target mares are missed. This means that photos or descriptions of each mare must be kept, or that darted mares must be identifiable in some other way e.g. be tagged with a different coloured paint each time they are darted. The Assateague Island horses managed by fertility control each have a name or code e.g. ‘Dee’s Heart X15P’ and ‘T5AFPAR Arianna’ and are fully counted six times a year[4]. While this kind of identification can work with 40 or so mares in a small area bounded by sea, it would not be workable for thousands of mares free to move within KNP’s 6900 sq km.
2. The person delivering the dart needs to be able to fire the dart from, at the furthest, 50 metres from the mare[5]. Assateague Island horses are more habituated to humans and thus far more approachable:  on the island, 2.1 million visitors a year[6] fit into just 63 sq km.  In Kosciuszko, 3.27 million visitors[7] fit into 6900 sq km, and most of those are visitors to the ski resorts in winter rather than to the areas occupied by horses. Although some horses near popular camping areas in KNP have become used to humans, most are very wary and will move away rapidly if people are within 100 metres.
3. Unlike Kosciuszko, most of Assateague can be readily accessed by people tasked with darting or rounding-up:  by boat, regular vehicle or over-sand vehicle.
4. Round-ups in the reserve on the southern part of the island occur on almost-level ground and through shallow sea water, reducing the risk of injury to horses and people.

In summary, Assateague Island is one example that supports CSIRO’s general conclusion that ‘Throughout Australia … horse herds are … poor choices for the successful application of currently available fertility-control agents.’ [8]

If horses are shot and their carcasses left on the ground, won’t that feed feral pigs and increase the pig population?

We agree that feral pigs cause substantial damage to the environment of Kosciuszko National Park and other areas, and that feral pigs will feed on horse carcasses if they have the opportunity[1] .

But if the NSW government’s current policy of not shooting horses in Kosciuszko National Park continues, feral pigs will have an assured food supply from horses that die naturally. That food supply will be distributed widely through Kosciuszko NP and will increase forever.

In addition, where feral horses are shot close to tracks that are suitable for trucks, it would be feasible for their carcasses to be removed.