Author:
Bayne Paul,Harden Bob,Pines Ken,Taylor Ursula
Abstract
The success of aerial shooting to control feral goats in arid and semi-arid
environments has lead to its widespread use in rugged and more densely
vegetated terrain elsewhere in Australia. In this experiment, the
method’s effectiveness with and without the aid of ground spotters to
assist in locating goats was evaluated in such terrain in the Chandler River
Gorge near Armidale, New South Wales. The abundance of goats was estimated by
applying a correction factor (1.45) to indices of abundance made by ground
survey. Ground observers monitored success during the cull. Overall, only
31% of an estimated 462 goats were culled, at an average cost of
$61 per goat. In all, 50% of the goats were in herds never seen
by the helicopter crew, while the remaining 19% were individuals that
escaped (17% unseen from the air) from herds that were shot at.
Inconsistent culling success, combined with marked differences in the
behaviour of goats in different experimental blocks, suggested that variable
prior exposure to aerial shooting had a significant and confounding effect on
the experimental outcome. Where goats had no prior experience of aerial
shooting, culling success was 40% without spotter assistance and
59% with spotter assistance. Where there had been a history of aerial
shooting the ground observers reported a marked increase in evasive behaviour,
and the cull was only 21% even with spotter assistance. These results
show that aerial shooting is not as successful in this type of terrain as has
been assumed and suggest that its repeated or exclusive use will result in
declining effectiveness as goats learn to evade the helicopter.
Subject
Management, Monitoring, Policy and Law,Ecology, Evolution, Behavior and Systematics
Cited by
18 articles.
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