Beneath the rushing traffic on the Sorell causeway at Midway Point exists a netherworld that most drivers and cyclists will never see.
It’s a world inhabited by some of the most remarkable wild creatures on the planet, birds capable of ultra-marathon journeys, sometimes straining the limits of endurance in 8000 km non-stop flights.
The hidden world of migratory shorebirds has been revealed in recent years by satellite tracking devices which record not only the length of their incredible journeys, but how far they travel in non-stop hops.
The inter-continental travellers leave our shores in early autumn for their breeding grounds in the far north – some within the Arctic circle – and start to return in late August. I’m always on hand at Orielton Lagoon spanned by the causeway to welcome their return.
When I see the first of the arrivals as winter turns to spring I always find it hard to comprehend that most of them would have made a round trip of 27,000 km in just a few months.
The 25 migratory shorebirds – also called waders – that reach Tasmania are at the end of their range along the East Asian/Australasian flyway. They are all remarkable in their own way, but for me one of the largest, the bar-tailed godwit, can only be described as sensational if its endurance is taken into account.
In the early days of tracking shorebird movement, the waders were fitted with bands on their legs after being netted. Although this system revealed the length of journeys, it did not answer the question of how many stops they made during their flight.
There was a theory they might fly non-stop for days and this was confirmed when satellite trapping techniques were developed in which the exact time and pace of these journeys could be recorded.
A male bar-tailed godwit fitted with a tracking device in New Zealand became known as the “long-haul king” when on his return journey from breeding grounds in Alaska, he flew one leg non-stop for 12,854 km. This represented the longest recorded non-stop flight by any land bird. The flight to a bay near Auckland took 11 days in total, the non-stop portion covered in just eight days.
Although endangered and increasingly rare along the east coast of Australia and in New Zealand, the bar-tailed godwit can still be observed on the wetlands of Orielton Lagoon during the summer months. But another of the larger waders, the eastern curlew, has become virtually non-existent in recent years. The curlew was once so numerous its flights of thousands of birds blackened the skies over Midway Point and Sorell.
Wader decline – 95 per cent in the curlew’s case – is attributed to the reclamation and development of wetlands along their migratory route embracing 22 countries, some of these nations with the most densely populated human spaces on earth.