Feral Animal Control
When the government of Western Australia bought the Peron pastoral station back in 1990 a full suite of introduced animals were present. Feral animal control began with the removal of over 15 000 sheep and cattle by 1994 using mustering and shooting programs. More than 12,500 goats were also removed in the early 1990’s and even though small numbers of goats persist to this day they are kept in check by a regular shooting program.
Rabbits are also present on the peninsula and their population fluctuates throughout the year. The use of diseases such as myxomatosis and in more recent times the rabbit calicivirus has helped to control the local rabbit populations but the most effective control has proven to be the seasonal variations in climate, which usually severely restricts the rabbit population in late summer.
This has proven to be the program’s most critical factor in trying to recreate an environment in which local fauna can re-establish itself. The removal of foxes marked the official beginning of Project Eden in 1995.
Enormous numbers of foxes (estimated at 2,500) and an unknown number of feral cats prowled the Peninsula when the control program began. Road kills were rarely seen as they were scavenged almost immediately, and studying the animal tracks on the sandy roads gave no sign of what other animals were living there, as nothing but fox tracks could be observed.
Virtual elimination of foxes was achieved in the first year of the fox control program when dried meat baits containing the 1080 poison were dispersed by hand or dropped from aircraft across the whole peninsula.
Baiting of the peninsula continues to occur several times a year in a comprehensive program, which lays approximately 60,000 baits annually, and removes any new foxes that may migrate into the protected area.
Feral cats are also susceptible to the 1080 poison, but are reluctant to eat a meat bait if there is plenty of other live prey to be had. Because of this behaviour, it has proven much more difficult to control feral cats on the Peron Peninsula. DPaW staff have spent a great deal of time in refining the baits to make them more palatable to cats and at favourable times, have been successful in killing up to 80% of cats prowling the peninsula, depending on the seasonal conditions and amount of prey around.
In the late 1990’s intensive leg-hold trapping was carried out for both research and population control of feral cats. Innovative lures using different sounds and smells were used for a number of years , and much information was gained about the breeding, behaviour and diet of these cunning predators, whilst helping to keep their numbers low.
The cat’s reluctance to consistently take food baits and wariness to enter traps, hampered the success of the eradication program and even though numbers were significantly reduced at times, they were never totally eliminated. The success of the reintroductions of some native species has also prevented the continued intensive use of the cat trapping program, as it has proved almost impossible to keep inquisitive bilbies and woylies out of traps.
As a result, aerial 1080 baiting is now used as the only method to control cat numbers. It is most successful when there is very little natural prey available to cats at the end of severe drought conditions. And although this is infrequent, it can at least give the small mammals a breathing space to bounce back under reduced predation pressure, if the baiting is soon followed by good rainfall.