When we think of wrecks, we think of shipwrecks, and the devastating power of the sea. But in the past few years, along Tasmanian and mainland coasts, another kind of wreck has been happening with increasing frequency. And no-one knows exactly why. …But it seems the sea is not to blame.
Too often in recent years, Tasmanian and mainland beaches have been littered with masses of dead, long-winged sea-birds. Closer inspection has revealed that they are Tasmania’s iconic “muttonbirds” (short-tailed shearwaters). (1) Scattered over the sand, these strange die-offs are called “wrecks” by biologists, and why they seem to be increasing remains unclear. Is it ‘natural’ causes, or is something more suspicious going on?
What do we know that could help solve the riddle? Short-tailed shearwaters are migratory. After summer breeding on our coasts and capes, the Tasmanian flocks fly north to the Arctic every autumn; first the adults, followed by the fledglings a month later. (2) Sailors who encounter them at sea describe the thrill of suddenly being among them; swirls and wreaths of long slender wings, flying fast, surrounding the boat and gone. They are fantastic oceanic fliers, but with a 30,000km round trip in as little as 6 weeks, many don’t make it, washing up exhausted and starved on beaches along the way.
But major wrecks, of hundreds of birds at once, do seem to be increasing. Are there fewer fish? Stronger storms, which could batter already-fatigued birds beyond their ability to survive? Researchers are only just beginning to look into the problem. But meteorologists now have enough data to show that climate scientists’ predictions are (depressingly for shearwaters) looking accurate: extreme weather events are on the rise. (1) And here is another question: does it count as death by ‘natural’ causes, when wind and storm strengths are breaking previous records- and if the culprit behind this may not be ‘nature’, but us.
There’s a lot of detective work still to do, to solve the case of the shearwater wrecks. Luckily, shearwater numbers are still high. Looking on the bright side, this means there will be time for a new generation of passionate young Tasmanians to turn into fully fledged ornithologists, marine biologists and other scientists, ready to take on the world to safeguard our muttonbirds, and ensure sailors are thrilled by their encounters for centuries to come.
Text was originally published as part of Amazing Science Stories, supported by Inspiring Australia
Images by Tasmanian Geographic.
1. Gough, D. 2013. Dead birds “not just a freak event”. Sydney Morning Herald. 13 Oct, 2014.
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