Chimney Swift

Fascinating facts about the Chimney Swift

• A chimney swift spends 10 months of the year airborne — sleeping, eating, mating, and even collecting nesting material while flying. They land only to breed, and their feet have evolved into little claws that can cling to vertical brick and stone. When you see one cutting sharp angles through the sky at dusk, it hasn't touched solid ground in weeks.
• These birds produce a saliva-glue stronger than commercial adhesive. They stick their nest — a small cup of twigs — directly to the inside of chimneys by coating it in their own spit. The nest holds firm through spring rains and the vibrations of a working fireplace below, held up by nothing but the bird's own biology.
• A chimney swift's heartbeat can slow from 500 beats per minute to nearly zero when it sleeps mid-flight, entering a state of torpor so deep that early naturalists thought they hibernated inside chimneys over winter. They actually migrate to Peru, but for 200 years people believed these birds disappeared into the earth itself.
• Urban chimneys have replaced their natural nesting sites — hollow trees — almost entirely. Before 1900, they nested in old-growth forests across eastern North America. Today, over 90 per cent of the population breeds in human structures. They've become a byproduct of our cities, so dependent on our architecture that their numbers plummet whenever we cap or remove chimneys.
• Chimney swifts hunt insects in the space where the atmosphere meets the city. A single bird can catch 600 mosquitoes and other small insects in a day, all in open air, using echolocation-like clicks and their tail feathers (which form a needle-point longer than their body) to steer through crowds. In losing them, we lose thousands of tonnes of natural pest control each migration season.

At a glance

About the Chimney Swift

As the sun sets over the urban landscape, a dark, cigar-shaped silhouette darts and weaves through the sky, the Chimney Swift's agile form a blur of motion as it chases down insects with reckless abandon, its shrill, repetitive call echoing off the brick and steel canyons it calls home. With its broad, rounded wings beating at a furious pace, this diminutive bird is a whirlwind of energy, its very existence a testament to the enduring power of adaptation in a world of concrete and steel. As it banks and turns, its feathers glisten with a subtle, sooty sheen, a reminder of the smoky origins of its name and the precarious balance it strikes between life and extinction.

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