Species of the Month – Swift (Apus apus)
Look! They’re back! Look!
They’ve made it again,
Which means the globe’s still working, the Creation’s
Still waking refreshed, our summer’s
Still all to come-
Swifts – Ted Hughes
Perhaps the most wonderful day of the year holds that magical moment when the Swifts return with high-pitched, intensely-exuberant screaming as they race through the air, then hurtle window-height down the road with graceful power and agility and then off again, spiralling into the sky. They tend to be heard first, then seen. The name Swift, like the adjective, comes from the Old English swifan – moving fast: the arrival of a speeding flock of these birds rapidly changes a quiet, early summer day into something wilder, thrilling and more joyous.
Swifts spend most of their lives in the air where they feed, mate and sleep – only requiring a warm breeze to waft upwards the insects, or ‘aerial plankton’ on which they feed. They are supreme aeronauts with sickle-like wings and streamlined bodies that allow for their lives to be lived well beyond our earthbound existence. It is worth bearing in mind that to achieve the same wing-length / weight ratio as these birds, most humans would require wings that were more than 500 metres long.
Their legs are too slight for walking, though they are able to grip onto surfaces such as walls with their sharply clawed feet and can crawl about on the ground if necessary. The ancient Greeks assumed they were footless and this gave them their scientific name (apous – without foot). They are unrelated to Swallows and Martins to which they are only superficially similar.
Swifts only come to earth to breed and despite their being so uninvolved with the terrestrial world, over time they have become associated with human settlement, nesting in the eaves or on the rafters of buildings, gaining access through cracks in the structure (where they can – modern housing and neatly repaired older buildings are usually useless to Swifts). They pair together for life and return to the same site year after year, building shallow, cup-like nests of grass, feathers and wind-blown detritus. The parent swifts may fly up to 600 miles a day, often travelling around continental low-pressure systems, to feed the growing chicks (who have the remarkable ability to lower their metabolic rate if food is not forthcoming). They may catch up to 100,000 small insects in a day. After fledging the young birds, who might not nest until their fourth year, remain aloft for the whole of their early lives, making their intercontinental journeys each autumn and spring. In a Swift’s lifetime, usually around nine years, they can fly as much as 1.5 million miles.
Swifts are an avian incarnation of the season. They mark the beginning of summer and they also delineate its close. Adults are the first to head south in August, followed by the young. The birds spend the European autumn and winter rocketing through African air until the wheel of the year turns again… and they’re back!