China ports threaten Aussie migratory bird

Imagine flying five days non-stop from Australia to China without any food or sleep.

The threatened great knot does just that on a journey of more than 5000km.

But port developments in Korea and China are destroying the migratory bird's habitat, with many of China's mudflats lost to development.

"It is crucial for this bird to stop in China because from such a long flight it has lost of a lot of its body fat and needs to feed," said ecologist Phil Straw.

"When there is nowhere to feed, they can't stop in China and therefore they can't go up to the breeding ground, hence the population has been declining."

China is a stopover on the way to Siberia, where they stay for two months to breed before returning to Australia.

A great knot left Broome last month and was recorded five days later in the southern Chinese province of Zhejiang.

"The great knot as well as many other bird species can go a long way without water or rest," Mr Straw said.

"We don't know how these birds do it.

"It's possible they are able to rest one side of their brains as they fly."

The vulnerable species spends most of the year on mudflats in Queensland, Western Australia and some parts of northern Australia, before heading north.