Flying for their lives
Every year, millions of shorebirds fly between Australasia and the Arctic. But for many, this will be their final flight.
Every year, millions of shorebirds fly between Australasia and the Arctic. But for many, this will be their last flight.
THE FIRST EXPERIENCE OF AUSTRALIA, for most international visitors, is an area of destroyed shorebird habitat: Sydney (Kingsford Smith) Airport. This flat tidal zone once provided a feeding point for thousands of migratory shorebirds. The birds still appear, but in far smaller numbers. Every year they come to Botany Bay, and other mudflats across Australia and New Zealand, to eat. They aim to get so fat they’ll look like tiny, feathered sumo wrestlers .T hey’re migrating to chase an eternal spring and summer, and the seasonal blooms of food that come with it – the Arctic Circle’s mosquito boom in June and July; Yellow Sea mudflats teeming with shellfish in April and May; and the shores of Australasia in November and December.
The act of migration isn’t exceptional, but the distance of this migration is. In 2007 a female bar-tailed godwit was tracked flying 11,680km from Alaska to New Zealand in nine days straight. It is the longest recorded bird flight on the planet. It seems perverse that a bird that can fly far enough to get to the Moon in its lifetime is so fragile, but the bar-tailed godwit and its fellow shorebirds – snipes, stilts, stints, turnstones and curlews, among others – face enormous, perhaps insurmountable, challenges.
The populations of the eastern curlew and the curlew sandpiper have declined by more than 80 per cent in the past 50 years, and seven of Australia’s 37 migratory wader species are near extinction. Shorebirds are not seabirds, they are waders – without webbed feet, they only go into the water as long as they can touch the bottom. So they survive in a place in between the sea and the land: the area revealed each day between high and low tide.
This type of habitat exists all along the East Asia-Australasia Flyway, the migratory shorebird highway that 8 million birds use to travel from Australia to the Arctic Circle. It takes in 22 countries – from Bangladesh and Myanmar in the west; to Australia and New Zealand in the south; and Russia and the USA in the north. And all along this route, intertidal zones are under threat. The flyway is on the brink of collapse.
The Wiggins Island Coal Terminal looms on the Queensland mainland, separated from nearby Facing Island by a few kilometres of water and tidal flat. It’s one of Australia’s major coal export hubs. Enormous bulk carriers sit in the water, lining up to take on their cargo and bring it up the flyway to China.
Not far away, a critically endangered eastern curlew stalks the tide, probing the muddy flats. In a few short months, it too will leave for the Yellow Sea. But, unlike the tanker, it will be under its own steam. Observing them is Associate Professor Richard Fuller, wet to his chest, muddy, and dragging a makeshift sled across the mudflat.The University of Queensland academic and his team are trying to find out what birds such as the curlew are sucking up when they stick their beaks in the mud.
Shorebirds have evolved to be specialised feeders; each species has a different leg length and its own idiosyncratically shaped bill. Some are curved, for poking down sloped holes in the mud, while others are short, for picking prey off the surface. Then there are those that are long and have touch-sensitive tips, for locating animals deep in thick mud.
These adaptations spread the feeding load across the mudflat so that different species do not compete for a single food source. But in the modern world, these ingenious and specific adaptations are also dangerous – if a habitat is disturbed and there is no prey, birds die.
“It’s really death by a thousand cuts,” Richard says, looking across the water. “So ‘a piece gone here, a piece gone there’ can build up over the years to substantial impacts. These birds aren’t just declining in the abstract sense, they’re heading towards extinction. Every time a species goes extinct, we lose something that we can’t get back.”
Bar-tailed godwits can fly more than 11,000km non-stop between Australia and the Arctic Circle (p64).
ByB the time they arrive in Australia, the world’s recordr holders for nonstops flight have lost nearly halfh of their body weight.
The mudflats near Sydney (Kingsford Smith) Airport were once alive with many thousands of migratory birds.