PhD study, Brolga & Sarus Crane

Tim Nevard completed his PhD studying interactions between Brolga and Sarus Cranes in Australia with the Research Institute for Environment and Livelihoods, Charles Darwin University, Australia. Tim and colleagues have recently published an important paper on Sarus Crane genetics, which establishes the Australian Sarus Crane Antigone a. gillae as a distinct subspecies, clearly separated from populations in south Asia, Myanmar and south-east Asia. Data from a single specimen from the Philippines, where Sarus Cranes are extinct, suggests a more recent separation from Australian Sarus. This implies that Australia may be a possible source for repopulating suitable areas of the Philippines with Sarus Cranes, should that become possible in the future.

A brief report of project results on hybridisation between Brolgas and Sarus Cranes (‘Sarolgas’) can be found on Ozcranes here». Other genetic work by Tim and colleagues has shown for the first time, crane migration between the Gulf of Carpentaria breeding area and the winter (or dry season) flocking area on the Atherton Tablelands. Tim is expanding this work on evidence for crane migration, using DNA from collected feathers. He is also conducting research on the almost unknown New Guinea Brolga» population. Tim is a member of the Crane Specialist Group».

Key issues

Brolgas and Sarus at Mareeba Wetlands, N Qld

Sarolga and Sarus Crane, Atherton Tablelands 1972 (courtesy G Archibald)

There are four main themes in Tim's PhD research. Firstly, the longstanding mystery of Brolga/Sarus hybrids (‘Sarolgas)’, first sighted in 1972 (see below), but the extent of hybridisation and implications for northern Australian crane conservation were not known. Secondly, how do the species occupy the same wintering area on the Tableland, do they compete, or do they differ in their food preferences and foraging locations? Thirdly, there have been conflicts between cranes and farmers in this area, how do the conflicts arise and what can be done? And finally, how closely related are Australian Sarus to other populations in Asia – contrary to other genetic analyses, are they separate subspecies?

Study background

In 1980, crane researcher and joint founder of the International Crane Foundation George Archibald, presented a paper to the International Crane Symposium in Sapporo, Japan. In ‘Introducing the Sarolga’, he described apparent Brolga-Sarus hybrid cranes seen on the Atherton Tablelands during his 1972 trip to Australia. George Archibald's suggestion that interbreeding is recent and increasing, and may threaten the future of Brolgas in northern Australia, has been one of the intriguing themes interesting Australian crane observers and researchers ever since.

When Tim began his PhD work in 2013, the annual North Queensland Crane Count» at Tablelands crane roosts from 1997, had established that Sarus Cranes concentrated in the central Tablelands, while Brolgas concentrated further to the south-west around Ravenshoe. In 2008 preliminary results on Sarus Crane numbers and distribution from these roost counts supported the nomination and determined the boundaries for the Atherton Tablelands Key Biodiversity Area with the Sarus Crane as the trigger species. But it was unknown whether feeding areas mirrored the species' distributions based on roost counts. With the longstanding question of Sarus Crane sub-species, the genetic analyses in this study have been able for the first time, to incorporate DNA from the extinct Phillipines population to compare with samples from Australia, SE Asia and India.

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Tim Nevard research Part 2»

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