Fly­ing for their lives

Ev­ery year, mil­lions of shore­birds fly between Aus­trala­sia and the Arc­tic. But for many, this will be their fi­nal flight.

Australian Geographic - - Contents - STORY BY ANN JONES

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.

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