Trial re-introduction of the woma python in northern South Australia

Summary

The woma python (Aspidites ramsayi), Vulnerable in South Australia and Critically Endangered in southwestern Western Australia where it has not been seen since 1980, was trialed for reintroduction into the predator-free, 60 km2 Arid Recovery Reserve in northern South Australia, a fenced exclosure that had already successfully restored four locally extinct mammal species since introduced cats, foxes and rabbits were removed in 1997. Ten captive-bred snakes from a single clutch produced at Adelaide Zoo, sourced from wild-caught parents captured within 400 km of the release site to preserve regional genetic provenance, were surgically implanted with radio transmitters and held in disease isolation from 2004 until release, screened repeatedly for ophidian paramyxovirus and inclusion body disease given recent outbreaks in Australian captive reptile collections. In September 2007, nine snakes (one transmitter having failed) were transported to the reserve and released: five hard-released directly onto dunes near disused bilby burrows, and four soft-released into a 0.5-hectare acclimatization pen pre-baited with oats to boost rodent prey density. Daily radio-tracking through daylight hours found the womas sheltering in burrows, moving shelters roughly every five days, traveling up to 230 meters, and successfully feeding after release; however, all nine released pythons were killed within four months, most likely by mulga snakes, a predator not anticipated during planning. Major difficulties included a two-year delay from disease-testing requirements with no domestic testing facility, and womas easily scaling the soft-release pen's containment fence. The project rates itself a Failure, though it yielded valuable new ecological data and raised public conservation awareness through extensive media coverage.