The muttonbirds that breed in Tasmania are known for their long-distance flights linking Australia to the far-north of Asia but one bird last year decided to go global in a different direction.
In June, a muttonbird was found on a beach in Ireland, making it the first of its species discovered in Europe.
The Irish bird-watcher who found the muttonbird – called the short-tailed shearwater beyond our shores – could not believe what he had stumbled across at first. Initially the birder thought it might be a Manx shearwater more commonly seen in the North Atlantic but there was something different about this bird.
The shearwater had washed up exhausted and hungry at Tramore Bay in County Waterford and it was immediately rushed to an animal rehabilitation centre where the veterinarians tried in vain to save it.
The dead specimen, however, enabled ornithologists to take measurements of its wing feathers and the length of its beak to establish exactly what of many shearwater species it might have been. They soon discovered it was a short-tailed shearwater from Australia, possibly one of the millions that breed in Tasmania each year.
With a population estimated at 30 million, the short-tailed shearwater is the most numerous of Australian seabirds and Tasmania is its stronghold. Vast rafts of shearwaters are common in the Derwent and along other Tasmania coasts at this time of year and muttonbirding was enshrined in not only the folklore of the European settlers but the 30,000-year history of the first Tasmanians.
The discovery of a species never seen before in the Palearctic bio-region – embracing the whole of Europe, eastern parts of Asia and North Africa – has been the cause of much celebration among birders in Ireland, no doubt some celebrating this rare edition to their checklists with pints of Guinness.
But recent research into the movements of short-tailed shearwaters in the Southern Ocean, particularly their foraging patterns in near Antarctica, suggests they might include the South Atlantic Ocean in their flights across vast regions.
A team of three researchers reported that on a voyage crossing the extremity of the South Atlantic they had observed vast flocks of shearwaters more than 2000 km west of the documented range of the species.
According to the researchers’ paper published in the Polar Biology journal, the birds were seen in the vicinity of Bouvetoya, an island forming a chain with South Georgia and the coast of South America to the west and the St Helena and the coast of South Africa to the east.
It is in fact a gateway to the Atlantic, a route which the short-tailed shearwater found in Ireland crossed at some stage after the breeding season last summer.
It may well have been one of the shearwaters I watched on the Derwent a few days into the new year. I like to think so.