Eagles did not walk to Tasmania after all

The wedge-tailed eagle probably arrived in Tasmania much more recently than was previously thought.

The magnificent wedge-tailed eagle or 'wedgie'.

19,000 years ago much of the world was covered in ice. Most of the rain that fell on the land froze and because of this the sea level was about 120 metres lower than it is today. Back then, many places that are now islands were connected to continents by what we call 'land bridges'.

Until about 12,000 years ago you could walk from mainland Australia to Tasmania.

When the ice melted and the sea level rose, many animals and plants became trapped on these islands.

Bass Strait (in blue) used to be land.

This is what scientists used to think happened to the Tasmanian wedge-tailed eagle.

But it turns out that wedgies probably arrived in Tasmania much more recently than that. Scientists at the University of Tasmania compared the DNA of Tasmanian wedge-tailed eagles with the DNA of mainland wedge-tailed eagles. Differences in DNA can tell us how long ago the two populations separated. It turns out that there are not enough differences for the separation to be 12,000 years. They now think that wedgies arrived in Tasmania sometime between 200 and 1000 years ago.

Not that kind of wedgie.
Source Simpsons Wiki.

In other words they flew. Or possibly they swam. But probably they flew. Or maybe they caught the Spirit of Tasmania

The shortest distance from the mainland to Tasmania is 240 kilometres, but it is possible to 'island hop' and travel via King Island in the west or Flinders Island in the east, which are about half-way. At least two wedgies, a male and a female, must have made the trip at about the same time to establish a new population in Tasmania.

The eagles probably didn't choose to fly hundreds of kilometres across the sea. It is more likely that they got caught in a storm and got lost.

Wedgie links

• The ABC talked to one of the scientists about ways this research might help conserve the Tasmanian wedge-tailed eagle.
• The wedge-tailed eagle is one of the largest eagles in the world. Find out more at the Australian Museum
• Healesville Sanctuary near Melbourne has a bird show that features an extremely close encounter with a wedgie.
• 240 kilometres may be a long way for a wedgie to fly, but that's nothing for the bar-tailed godwit, which can travel for more than 11,000 kilometres without stopping for a rest.