What are the Rangers up to?
Paul Helleman (RIC) and Bree Hunter (Wildlife Ranger) spend a significant amount of their time in the field. Over the past few weeks they have been busy conducting the annual king penguin chick census and monitoring the breeding success of the island’s grey petrel population.
Grey petrels (Procellaria cinerea) are listed as endangered by the Tasmanian Threatened Species Act. They breed on cool temperate and subantarctic islands over winter and Macquarie Island is their only known breeding location in Australia. Grey petrels were first recorded as breeding on the island in 1900 but an eighty year absence followed, and were therefore considered to be no longer present. However, in 1999 three burrows were found with evidence of recently fledged chicks. The timing of this discovery coincided with the final stages of the cat eradication program, suggesting the re-colonisation of the species.
Burrowing petrels are vulnerable to introduced pests, particularly cats and rats. Petrel eggs are a tasty treat for rats and immobile chicks are an easy meal for cats. Shortly after the success of the cat eradication an adult bird was found incubating an egg and breeding activity on the island has continued to increase ever since.
The island’s three largest colonies are monitored throughout the winter. This year has proved to be the most successful thus far, with seventy-two chicks actively sitting in burrows. It’s suspected that most of these chicks will survive and leave their burrows in October to spend their first few years of life at sea. They’ll eventually return to shore in order to breed.
Macquarie Island’s grey petrel population is expected to continually increase as a result of recent eradication efforts.