WITH DON KNOWLER

The equinox came and went last autumn and I didn’t notice. Funny that, because I’m always confused by a moment in time divided equally between night and day.

I’m not alone because sometimes birds forget to migrate during the equinox in mid-March and start to sing because they think it’s spring.

Not so the longer division of day and night, the winter solstice on June 21 this year, which recorded the longest night at the same time the northern hemisphere recorded the longest day.

You know where you stand with the solstice. It’s that mysterious moment, the extremes of seasons, when we are reminded all life on earth is connected to the heavens. The seasons are caused by the tilt of the Earth’s rotational axis away or toward the sun as it travels through its year-long path around our star. Perhaps the power of the celestial connection has been lost because we no longer need the stars for navigation like the mariners of old. We use satellite navigation systems but many of our bird species still rely on the celestial world to plot their course.

The link to space was perceived in faroff times but not quite in the way we understand it today. At about the time Tasmania was settled by Europeans, it was believed swallows migrated to the moon in winter. It was only later established that the European swallows breeding in Britain and western Europe in summer were the same ones seen by seafarers going ashore at Cape Town at the southern tip of Africa.

Tasmanian welcome swallows travel to the Australian mainland in winter.

Some birds do indeed use the stars to aid navigation. Although much still has to be learnt about avian migration, it is believed the birds that fly by night can read patterns of stars to aid navigation. This gives them a sense of direction – establishing north-south, east-west – to undertake their often epic journeys. They also read the position of the sun as a compass and tune into the Earth’s magnetic fields, strongest at the equator and weaker as they travel north or south.

Closer to historic breeding grounds or wintering areas, migratory birds are also able to determine landmarks like valleys, mountains and rivers.

And the journeys in many cases are truly epic. One seabird sometimes seen in Tasmanian waters, the Arctic tern, flies between the North and South Poles each year and some waders visiting Tasmania each summer fly to Siberia and Alaska, some nesting within the Arctic Circle.

At the time of our winter solstice, when our remarkable waders are breeding in the endless light of the tundra in the far north while we are cast in darkness, it’s worth considering the pull the moon, planets and stars have on our consciousness, and the physical rhythms of our lives. The birds map our pathways through the cosmological landscape.