The frosts came late to my home valley this year, but they prompted the same response when I saw the white coating on the lawn and an icy sparkle on the street beyond our drive: “What am I doing here?”
As I warmed my hands by the log fire, I lamented not joining the Tasmanian migration to Queensland to enjoy some warm weather there.
The mournful, melancholy winter song of the resident silvereyes coming from the frozen, rigid bottlebrushes seemed to be saying the same thing.
The silvereyes and I both had a choice, in my case before the pandemic lockdown took hold in March, we could have winged our way north when autumn ended, me by Jetstar, the silvereyes on fragile but robust wings, joining both birds and people with more sense than those rugging up to see out the unforgiving Tasmanian winter.
I’m sure the silvereyes – practical, no-nonsense birds well versed in the art of survival – would not see the funny side, the irony of two species so far removed in the evolutionary spectrum contemplating this same journey to escape the cold. Both in a common dilemma.
Although weighing just 10 grams, the Tasmanian silvereyes are capable of making an incredible journey of more than 1800 kilometres to southern Queensland. Strangely, a fair number choose to remain in Tasmania and take their chances here.
These are the birds I see feeding on berries and insects in my garden, enduring the cold and emitting a sad winter territorial song, in tune with my grumblings about the ice coating my car windscreen.
The question why some silvereyes stay and others depart is as great as the complex and mysterious business of migration itself. But at least research in recent years has cast some light on these miraculous journeys.
It appears migratory birds navigate by both the earth’s magnetic field and the position of the sun and stars. Most migration takes place at night, or during dawn and dusk. Also, they use landmarks along the way to guide their path. The practice of ringing the legs of birds has revealed them turning up in the same places year after year. One pair of Tasmanian silvereyes was caught and released in a Sydney garden three times over a four-year period. This indicates that the birds follow exact migration paths.
Various sub-species of silvereye are found across the coastal eastern, southern and western half of Australia but it is only the Tasmanian birds who have proven to be great travellers, determined that the potential barrier of the Bass Strait will not stand in their way.
Although Tasmanians visiting the Gold Coast for the winter are in the company of their Tasmanian counterparts, few realise it. The Tasmanian silvereyes, though, can be told apart because they have russet flanks on their grey and green plumage. They are also slightly heavier, perhaps carrying more muscle for the epic flight to escape ice and snow.