Thunder in the mountain, it sounded like the opening lyric of a Bob Dylan song. I should be seeking shelter, in a cave and not under a tree. I stood in the open, however, my eyes on the heavens. It was just the sort of storm front that would bring with it the mysterious and magical white-throated needletail swift. That or the rising hot air from a bush fire.
The swifts breed in Asia and migrate to Australia for our summer, guaranteeing a supply of their flying-insect prey year-round. For the swifts, it is an endless summer.
I’ve only seen swifts on two occasions previously in Tasmania, but I am always on the lookout for them when conditions are right. And so it happened in early February, purple rain clouds tumbling and rolling towards Mt Wellington from the west, and the tumbling and turning and twisting swifts carried before them, like flying fish riding the surf.
The swifts usually appear high in the sky, very high so they are mere dots, but the elevation of the mountain put them at eye level. They were moving closer ahead of the storm clouds, chasing insects disturbed by the gathering winds. The needletails are also known as stormbirds in parts of Australia.
The anchor-shaped needletail is one of the biggest swifts, about the size of a new yellow holland honeyeater and, along with its 100 or so other family members worldwide, represents a group of the most aerial of birds. Larger species are among the fastest fliers in the animal kingdom, with the white-throated needletail having been reported to fly at up to 170 kilometres an hour. One of the few birds to top that is the absolute master of the skies, the peregrine falcon.
From my vantage point at the Chalet about two thirds of the way up the mountain I was treated to the best of spinetail aerial displays. I could clearly see the white throat markings on a chocolate brown body that give the needletails part of their name. The term needletail comes from the short spiky ends to tail feathers.
There must have been 20 or 30 birds in the flock – it was impossible to count them reliably as they criss-crossed the sky – and as I watched them wheeling and banking, I considered a remarkable journey that each year brings the swifts to Australia, and a lifestyle that sees them spend most of the time on the wing.
It was once believed that they never came to ground out of the breeding season but the latest research suggests they do indeed roost in trees, if only for short periods. They certainly feed exclusively on the wing, and drink, and there is a commonly held theory they also mate on the wing. No one has ever proved otherwise.
Their diet includes flying insects, such as termites, ants, beetles and flies, which they catch in their wide gaping beaks. While feeding, the white-throated needletail protects its eyes with a special membrane and a small ridge of feathers.
Little is known of the breeding behaviour of this species except that courtship displays consist of a series of vertical flights. The eggs are laid on a platform sticks placed in a hollow or similar crevice high in a tall conifer.
As soon as these birds had appeared, they were gone again on their journeys across mountain and plain and, later, ocean and desert to nest in the rocky hills of central Asia and southern Siberia.
My previous sighting of the swifts came when I had attended a parent-teacher meeting at my son’s school. We must have appeared an eccentric family. As the teacher mentioned that she would prefer it if my son didn’t bring his basketball to class, his father had his eyes firmly fixed on the sky seen through the window behind her desk.