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Godwit in flight. Photo/Athena Drummond/Supplied

The search for the missing bar-tailed godwit

The story of GO2WRYB, one of the Bird of the Year 2015 species, highlights the fact that 80% of shorebirds and 90% of seabirds are threatened or at risk of extinction. 

For over a month GO2WRYB was missing, presumed dead.

That last sighting of the bar-tailed godwit – whose name is an acronym for the coloured bands on his leg – was at Brooklands sand spit just north of Christchurch in March this year when it was one of thousands of godwits preparing to set off on the 10,000 km flight to the rich feeding grounds around the Yalu Jiang Estuary on the Yellow Sea in southern China.

There, he would graze on the tidal flats before taking off on the next leg of his journey to the breeding grounds of the Yukon-Kuskokwim delta in Alaska where, in the melting permafrost of the Arctic tundra, he would gorge on insects, building up energy for the 11,000-12,000km return flight to New Zealand.

It is an extraordinary passage taking an average eight to nine days, the longest non-stop flight in the world undertaken by adult and juvenile birds as young as three months (Qantas’ new Boeing Dreamliner flight, in comparison, covers 16,200km in a trifling 19 hours). But without sufficient food or energy, birds can die or be so weak on their arrival they simply cannot feed.

So far this spring, about 6000 godwits have accomplished this return journey. At last count 4150 were spotted at the Firth of Thames. At the Avon-Heathcote/Ihutai estuary on Christchurch’s Southshore Spit, the first urban wetland in Australasia to become a recognised network site on the East Asian-Australasian Flyway for migratory shorebirds, Christchurch City Council ornithologist Andrew Crossland counted 1120 birds feeding on the polychaete worms.

Wrybills, which feed and breed on South Island braided river bank. Photo/Getty Images

But no sign of GO2WRYB – until yesterday, when it was spotted once again at the Brooklands spit feeding on worms.

GO2WRYB was needed to complete a story that began last year when university researchers in China augmented the dwindling supply of shellfish on the tidal flats of the Yalu Jiang nature reserve with stocks brought in from north China. GO2WRYB was spotted feeding at the newly seeded reserve in April last year. He was seen again in Christchurch in February, showing he had been able to eat enough of the emergency food supply to fly to Alaska then on to New Zealand. Spotting the bird here again this year would show he had been able to complete the entire migratory cycle.

Because many don’t.

In the late 1980s, just over 100,000 godwits were recorded in New Zealand. The most recent count, in November last year, logged 67,500. Keith Woodley, manager of the Pūkorokoro Miranda Shorebird Centre on the Firth of Thames, has been tracking the birds for 26 years. “When I came here in the 90s, we routinely had 9000-10,000. In recent years, we’ve been averaging around 5000-6000. The numbers have dropped about 30% over the past 20 years and the decline is continuing.”

The pinch point for the godwits is the vast expanse of tidal flats along the Yellow Sea in south China and North and South Korea. The Yellow Sea is a vital refuelling station for hundreds of thousands of migratory birds, including the largest known migratory population of bar-tailed godwits, red knots and great knots. But it is a precarious foothold. Two-thirds of the Yellow Sea’s mudflats have been progressively lost to land reclamation for agriculture, ports, industrial developments and urbanisation. In some areas, 60-90% of the coast is now barricaded by sea walls, impeding the usual flow of sediment down the Yalu River into the mudflats and triggering a decline in food supply.

Travel takes its toll: a godwit plump and primed for passage (left), and worn and thin after an 11,680km flight (right). Photos/Jesse Conklin/Supplied

The loss of such sites has a massive effect on bird populations. The construction of a 13km seawall in South Korea in the 1990s, reduced surrounding mudflats, a major staging site for great knots, by 41,000ha. As result of that one development, says Woodley, the great knot population has dwindled by 22%.

Because so much of the Chinese and South Korean coastline has been developed, alternative habitats, many including the largely untouched mudflats of North Korea, are already packed. “So you get this squeeze as more and more birds chase a finite food resource.”

Over the past 15 years, shorebird populations reliant on these intertidal areas have declined an estimated 50-70%. “And the more a population depends on the Yellow Sea during migration, the more trouble it is in,” says Woodley. The bar-tailed godwit populations that winter over in New Zealand and eastern Australia rely on the Yellow Sea stopover only on the northbound journey. A second population of godwit that breeds in Siberia and winters over in northern Australia stop at the Yellow Sea on both the north and southbound journey. That population is declining at over three times the rate of ours.

Even if godwits do reach Alaska, their troubles are not over. In the Arctic, they face predation by foxes, skuas, mink, cranes and ravens, customary harvest by the Inuit people and the risk of knock-on effects of changing weather patterns. “The chance of a young godwit chick surviving to become an adult,” says Woodley, “is not that good.”

Encroaching coastal development is shrinking their feeding grounds. Photo/Phil Battley/Supplied

Moored in Aotearoa

In New Zealand, godwits have a cultural mooring. They have links with iwi as a traditional food source and are potentially a bird that alerted people to the presence of land to the south. Community groups celebrate the arrival of the godwits; church bells have rung out their welcome; the bird appears in Robin Hyde’s novel The Godwits Fly, James McNeish’s As for the Godwits and Bridget Armstrong’s play Flight of the Godwit, often as a symbol of the long flight paths undertaken by adventurous Kiwis. But from a conservation perspective, these small brownish birds, living on the country’s margins, not even breeding here, have historically fallen out of the picture. Along with our two other international migratory shore birds, red knots and turnstones, it is only in recent years that the godwit was classified as a native to New Zealand, where it is now classified as “at risk”.

Back at the Avon-Heathcote/Ihutai estuary, the risks are hard to miss. As Crossland sets up his spotting scope to count the godwits (count the legs and divide by two, he quips), a large wolfhound lopes past the sign telling owners to keep dogs on leads. A neighbour tells of a quad bike owner who recently removed the bollard before heading onto the shorebird reserve.

Although the godwit population on the estuary is still robust, says Crossland, it now has to contend with more people: walkers, fishers, mountain bikers and kitesurfers (unlike yachts and windsurfers that take to the water only at high tide, kitesurfers can operate on the mid-tide when birds are feeding). Around the country, the resting habits of godwits are being disturbed by more coastal subdivisions, more vehicles and more campers.

Bird migration expert Phil Battley of Massey University recalls the grumpy resident living on an isolated stretch of the Firth of Thames who would berate people walking along the foreshore. “Birds roosted there. It was a good spot for them, but after he died, people started taking four-wheel drives along the beach. Now you get 50 campervans all the way along.”

These disturbances affect the birds’ roosting habits. Because godwits can’t feed when the tide is in – they can’t sit on the water or swim – they wait out the tide on nearby reefs or sandbars. If disturbed, they will seek shelter away from their feeding grounds, so using up precious energy reserves. “If they are doing this day after day, they won’t make it to the Yellow Sea,” says Battley. “Having a roost that is undisturbed, allowing them to sleep properly and preferably close to their feeding grounds, will help sustain that population. People who think it is fun to let their dogs run through the birds – it is not really that fun.”

Life on the margins of our rivers and estuaries is certainly not fun for many of our water birds and waders. As reported in the Ministry for the Environment and Statistics NZ’s recently released Our Marine Environment, 80% of shorebirds are classified as threatened with or at risk of extinction. Their habitat has diminished. Streams have been buried, estuaries filled in and connecting pathways degraded. Nine-tenths of our wetlands – important feeding grounds for birds and a filter, flood barrier and carbon sink for the environment – have disappeared, mainly for farming and urban development. Those that remain, says this year’s Environment Aotearoa report, suffer from pollution, invasive species, disrupted flows and the effects of farming, forestry and urban developments upstream.

Birds feeding or nesting on tidal islands, shell banks and estuaries are ready game for rats, cats, ferrets hedgehogs and stoats – last year a single stoat incursion at Te Henga (Bethells Beach) resulted in the death of about 70 northern common diving petrels. Off-leash dogs can frighten roosting birds or kill coast-hugging species such as pied oystercatchers and New Zealand dotterel.

Vehicles and dogs are threats to roosting birds. Photo/Alamy

Threats from land and air

The South Island’s braided riverbeds are vital feeding and breeding grounds for more than 80 bird species including wrybills, the only bird in the world with a bill that curves laterally; the banded dotterel; the nationally endangered black fronted tern/tarapirohe; the endemic black-billed gull/tarāpuka, the most threatened gull in the world, which was recently seen nesting, remarkably, amongst the foundations of a half-demolished office building in downtown Christchurch; and the black stilt/kakī. Although their pebble-coloured eggs are well-camouflaged against the airborne threats of harrier hawks and black-backed gulls, many of these birds are ill-equipped to deal with night disturbances, on-the-ground attacks from mammals or four-wheel drive vehicles running over chicks and eggs or frightening birds into abandoning their nests.

Community action is proving critical in preserving some of these threatened populations and the more understanding we have about our sea and shorebird populations, says Secretary for the Environment Vicky Robertson, the more likely we are to care for them. “If I know I have some iconic species in my backyard that only live in that backyard, then I might feel more responsibility in making sure they are there for my grandchildren.”

To preserve what we have, she says, requires everyone making different decisions on a daily basis – from trapping predators and clearing weeds to not littering on beaches or using the beach as a playground for our ever bigger toys.

“Small actions by many people do make a difference – it is likely some of our shorebirds would now be extinct without the work that has been done so far.”

Last year Canterbury’s Ashley-Rakahuri Rivercare Group volunteers won an Australasian Wildlife Management Society award for their work protecting the river birds in the braided Ashley-Rakahuri River. “There are the three things on the riverbed,” says chair Nick Lidgard. “Predators, the invasion of weeds and human disturbance. During the breeding season, we block off four-wheel drive access. We have an agreement with four-wheel drive clubs and [regional council] ECan, but still, even at this time of year, you see fresh four-wheel drive tracks.”

On the Coromandel, volunteer efforts to protect dotterels nesting on the beaches – trapping predators, fencing off nests, discouraging dog owners from walking dogs at this time of year – have had dramatic results. Although the Southern New Zealand dotterel is still classified as “nationally critical” (the highest risk of extinction), its northern counterpart has moved down the threat chart to “at risk”.

“But it is still conservation-dependent,” says Woodley. “If you stopped that kind of management, the population would fall.”

Management at sea is proving more difficult. Seabirds are ranked by the International Union for Conservation of Nature (IUCN) as the world’s most threatened bird grouping. With 15,000km of coastline and one of the biggest exclusive economic zones in the world, New Zealand does deserve its “seabird capital of the world” title. We have the greatest number of resident seabird species in the world (88 of a global total of about 370) and the largest number of endemic seabird species of any country. Nearly a quarter of all seabird species breed in New Zealand and 10% breed only here.

Vehicles and dogs are threats to roosting birds. Photo/Getty Images

Changing climatic patterns, habitat degradation, ocean pollution, light (last year, 67 Buller’s and flesh-footed shearwaters crashed aboard the Pacific Jewel cruise ship in Auckland after being attracted by the lights) and plastics are taking a toll. But the incidental capture and death through fishing remains the biggest threat, especially for albatrosses, petrels and shearwaters. Sea-birds are opportunistic foragers, spearing down for fish discards from fishing vessels and diving after baits, hooking themselves or becoming entangled in lines, colliding with net cables or getting caught in gill nets. Although by-catch is decreasing – from an estimated 8192 in 2002/03 year to 3328 seabirds in 2017/18 – the Our Marine Environment report says 90% of seabirds are threatened or at risk of extinction.

Reducing seabird by-catch requires on-vessel management and international co-operation – in recent years New Zealand has entered agreements with Chile and Japan to help protect these maritime species. But an international response to godwit habitats is giving Nelson ornithologist David Melville reason for “cautious optimism”.  

“Five years ago, I would have been all doom and gloom. The rate of destruction of coastal areas in China was dramatic and it looked as if we were going to have virtually no natural coastline left on the Yellow Sea.”

Last year, however, China’s National People’s Congress announced a stop to all major commercial reclamation projects on the coast, unless for urgent national interest. This year, two areas of the Jungzu coast were listed as World Heritage sites and more are expected to follow.

It has been a complete game changer, says Melville. “There are still massive problems on the coast but the fact the [Chinese] Government is promoting positive conservation management of the remaining coastline is fantastic. We could be looking at halting the decline in some of these populations.”

North Korea is also coming on board. Last year the country had two wetland sites listed under the international Ramsar Convention and has since been accepted into the East Asian-Australasian Flyway Partnership.

But as with so many of our marginal birds, the godwits’ foothold in this country is shaky. Back at the Avon-Heathcote/Ihutai estuary, the godwits were slow to arrive this spring. Last year, says Crossland, 218 birds had arrived by early September. This year, the flats were bare until the 20th of the month. “We were quite worried – is the day they don’t turn up the year they never come back?”

This article was first published in the November 2, 2019 issue of the New Zealand Listener.