The high-risk life of the Bar-tailed Godwit

From GJ Walter Park, just north of Toondah Harbour on the shores of Moreton Bay, Judith Hoyle gazes across the dappled water towards Cassim Island, a resilient stand of mangroves emerging from the mudflats several hundred metres offshore. Ferries from Minjerribah (North Stradbroke Island) cruise past, barely causing a ripple.

From a spit of mud on the island’s southern end, a group of 100 or so Bar-tailed Godwits appear undisturbed. But the rising tide is rapidly consuming their roost. As the spit disappears beneath the waves, the godwits reluctantly move to higher ground, deeper into the mangroves. By high tide, they will be forced further inshore, where dogs are allowed off-leash.

Hoyle, a BirdLife Australia board member, watches the godwits with a mixture of awe and concern. The birds are emaciated and exhausted, having only just arrived back in Moreton Bay from their breeding grounds in the Arctic tundra, which stretches from north-eastern Siberia to Alaska. They have barely any energy left, moving only when forced.

“Every time I talk about the migration of shorebirds, I come out in goosebumps,” Hoyle says.

Bar-tailed Godwits are endurance beasts. Last year, a satellite-tracked bird, just five months old, broke the record for a single flight, winging it nonstop over 13,500km from the Yukon Peninsula in Alaska to Tasmania in 11 days. While airborne, they sleep with one eye open, switching off half their brains at a time, navigating by the stars and the Earth’s magnetic field.

Once they arrive and spread out around the shores of Australia and New Zealand, the godwits have one purpose: to gorge themselves on all the molluscs, crustaceans and aquatic invertebrates they can eat until they are fat, feathered footballs, ready for the journey back.

It’s a high-risk, high-tension lifestyle. Like the Eastern Curlew and the 20 to 25 other shorebirds who depend on Moreton Bay as a non-breeding foraging ground each Australian summer, the birds cannot afford excessive disturbance. Hoyle and I look askance at the dog owner who lets her three pooches happily chase a Frisbee into the water 10 metres away.

“Every time a migratory shorebird is disturbed, they’re losing energy, which means two things can happen – they may not reach the critical weight to migrate, so they lose a breeding event. Or they set off and fail to make the migration and they die. If one bird was to live and breed for 15 years, the species loses every one of those breeding events,” Hoyle says.

Both of us are experiencing a kind of eco-grief. About 30 years ago, we would come to Moreton Bay to see tens of thousands of shorebirds lined up on the banks of Brisbane’s bayside suburbs of Cleveland, Thorneside, Manly and Lytton. Every year, we’ve watched their numbers decline.

The numbers of Bar-tailed Godwits appear to be, in Hoyle’s words, “relatively chipper” – they are still one of our more commonly encountered migratory shorebirds. But globally, the species has sagged from an estimated 1 million individuals to fewer than 300,000. In Moreton Bay, numbers fell by 68 percent from 1993 to 2008.

It is for these reasons that Hoyle has been fighting against Walker Corporation’s proposed development at Toondah Harbour, which intends to build out from the foreshore, consuming the park and mudflats in a concrete archipelago stretching to the boundary of Cassim Island.

“All this area that you can see in front of you is going to be high-rise, with 3,600 apartments,” she says.

And that, Hoyle says, means more water sports, more dogs, more noise, more claypans swallowed up, and more dead and displaced shorebirds. Moreton Bay, she says, is an intertwined ecosystem. “You can’t say we’re going to drop a rock and it’s going to have no impact; there’ll be a ripple-out effect.”

When the tide recedes, the vast mudflats of Moreton Bay will be exposed. One could be forgiven for thinking the godwits, and all the other shorebirds, will simply go somewhere else. The truth is they are remarkably site-faithful: tracking has shown the same birds return to their favoured locations, including Toondah, year after year.

Moreton Bay was declared a RAMSAR site as a wetland of international importance in 1993. It is also a marine park and a key biodiversity area. It is a summer refuge to a number of critically endangered birds besides the godwit. Eastern Curlews, Curlew Sandpipers and Great Knots – all trans-equatorial migrants from the Arctic Circle – can be seen with relative ease here.

Another chunk of a supposedly protected area falling under a developer’s hammer would be a gross failure of Australian environmental law, Hoyle says. “The EPBC [Environment Protection and Biodiversity Conservation] Act is failing to protect our most vulnerable family of birds by continuing to approve this development here, that development there. If you keep nibbling away at habitats, the birds will continue to decline.”

Hoyle is voting for the Bar-tailed Godwit in Australia’s bird of the year 2023 poll. Partly it is because shorebirds, collectively, have everything stacked against them. They live in the intertidal zone – inconspicuous, rather drab until they moult into often startling breeding plumage. The godwits morph from beige to beautiful brick-red before their journey north.

But mostly it is because of the extraordinary lives they lead. “I understand why people would vote for the Superb Fairywren and the magpie – these are birds that we see every day and they have a relationship with. But the Bar-tailed Godwit does something that is truly amazing. No other birds have that impact on me.”

First published in the Guardian, 28 September 2023

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