Agriculture, brolgas and Australian sarus cranes on the Atherton Tablelands, Australia

Abstract

Flocks of brolgas (Antigone rubicunda) and Australian sarus cranes (A. antigone gillae) congregate in cropping areas of the Atherton Tablelands in north Queensland, Australia, during the non-breeding months of May to December each year and sometimes come into conflict with farmers. The central part of the region has been declared a Key Biodiversity Area, largely because it is the only well known non-breeding area for the Australian sarus crane. We investigated spatial and temporal patterns of use of this landscape for foraging by the two species to determine how they might be affected by changes in cropping. Abundances of the species were positively correlated with each other over both time and space. Sarus cranes were nevertheless markedly more abundant on the fertile volcanic soils of the central Tablelands, whilst brolgas were more abundant on a variety of soils in outlying cropping areas close to roost sites, especially in the south-west of the region. Both species used a wide variety of crops and pastures but occurred at highest densities on ploughed land and areas from which crops (especially maize) had been harvested. In addition, brolgas were also strongly associated with early-stage winter cereals with volunteer peanuts from the previous crop. We conclude that maize and peanut crops are important as foraging sites for both species during the non-breeding season, a situation that requires management in the interest of both cranes and farmers, especially as cropping patterns intensify and agricultural technology changes. However, we also note that flocking on the Atherton Tablelands indicates that brolgas and sarus cranes are likely to be adaptable to change and able to take advantage of newly created cropping areas.