Basic surveys are urgently needed across northeastern Australia to determine important areas for breeding and non-breeding cranes, including the sarus crane, especially given efforts to intensify development in the region, says a group of ornithologists that include two Indians.
In a first-of-its-kind study, the ornithologists are monitoring the breeding area of the sarus crane in northern Queensland, where it shares the area with the closely-related brolga species.
These two species are very poorly studied in Australia and this is the first-ever, systematic, 3,000 km survey to determine ecological parameters for them, Mysuru-based Nature Conservation Foundation scientist K.S. Gopi Sundar told IANS.
"We carried out a multi-floodplain landscape-scale survey during April-May 2017 and derived metrics for several ecological aspects for the first time for both crane species," he said.
Large-scale developments currently planned in this region, with potentially major impacts on cranes, create an urgent need to understand the ecological requirements of each crane species, say the biologists in a paper that will go online next month by Emu – Austral Ornithology, the flagship of BirdLife Australia that is dedicated to creating a bright future for Australia’s birds.
The researchers used some high-tech methods — stable isotope analyses — to peer into the dietary habits of the two crane species using molted feathers.
The methods yielded some amazing new information of how the two species may be eating different things to enable their sympatry, said Sundar, also the Director of Programme SarusScape for the International Crane Foundation. (Two related species are said to be sympatric when they live in the same geographical area and often encounter each other.)
The field team, comprising two Indians — Sundar and Swati Kittur — and one of Finnish of Irish-origin (now both naturalised Australians) braved the remote outback along the Gulf of Carpentaria.
The collaboration included the Universities of Melbourne, New South Wales and independent crane researchers.
It is not common for scientists in India to think outside the country borders for work.
"For me, the choice was easier since the sarus is found in many countries outside of India and we need to include studies on their requirements everywhere if we are to work towards their conservation globally," Sundar explained.
The study says the abundance of the two species differed between the floodplains. Both crane species synchronised nest initiation with rainfall (November to March). Breeding success was higher than past estimates anywhere, with 60 per cent of sarus crane pairs and 50 per cent of brolga pairs fledging chicks.
The sarus crane, the globally threatened due to rapid land-use changes, including deforestation and agricultural intensification particularly in Southeast Asia, preferred four riverine eucalyptus-dominated regional ecosystems in Australia, with 10 per cent using open habitats.
The brolga preferred two non-wooded regional ecosystems, but 32 per cent shared the eucalyptus-dominated regional ecosystems with the sarus crane.
Stable isotope analyses revealed the sarus diet to comprise more diverse vegetation than the brolga, which fed across a wider range of tropical levels.
The Gilbert river floodplain had the highest counts and encounter rate of the sarus crane, while more brolgas were sighted in the Flinders river floodplain.>>