The Emus’ migration routes are also influenced by climate. As they can find more food in humid regions the birds wander always to places were rain was falling down recently. It’s not yet clear how Emus orientate themselves and can detect rain from several hundred kilometers away. Researchers believe this is a combination of sighting distant rain cloud formations, smelling rain, and hearing the far-off sound of thunder from distances the human ear cannot.
In Western.Australia, the 100-year-old fence, now called the State Barrier Fence, is the longest manmade structure in the state and is visible from space. It runs for 1170km through the state's southwest, from the Zuytdorp cliffs north of Kalbarri to east of Ravensthorpe.
Originally erected to keep rabbits from spreading westward, the fence is undergoing a multi-million dollar upgrade to protect more agricultural lands in the southwest from 'pest' species, including wild dogs, dingos, emus and kangaroos. It includes major plans for a new barrier, up to 700km long, through pristine woodlands leading down to Esperance, and $5 million has been put aside for that.
Viv Read, invasive species director for WA's agriculture department, says the plan is a response to the region's farmers, who complain of a rising incidence of wild dog attacks and crop damage from flocks of emus. "Extending the fence is a non-lethal way of controlling vermin and the alternative is baiting, shooting or trapping.
"The primary purpose and major benefit of the State Barrier Fence is to minimise emu impact on cropping areas," Viv says. "Major emu migrations occur about one year in seven.