Swift

A life without landing

Swifts are the most aerial of all birds. A swift that lands on flat ground cannot take off again — its legs are too short and wings too long to generate the upstroke needed to launch from a surface. They must fall from a height to become airborne.

In compensation, they’ve mastered everything else in the air:

• Sleep in flight — using unihemispheric slow-wave sleep (one brain hemisphere at a time) while soaring at altitude
• Mate in flight — brief aerial copulations
• Bathe in flight — flying through rain or skimming water surfaces
• Collect nesting material in flight — catching floating feathers and seed fluff

Young swifts that fledge in late summer fly non-stop to sub-Saharan Africa and may not land again for 2–3 years, until they return to breed.

The fastest level flier

The common swift holds the record for the fastest level flight of any bird, measured at 111.5 km/h during feeding chases. The Alpine swift (Apus melba) has been documented flying 200,000 km in a 10-month migration without landing.

Screaming parties

On warm summer evenings across European cities and villages, groups of swifts chase each other around buildings in tight formation, screaming continuously. These “screaming parties” are groups of non-breeding young birds (1–3 year olds) engaging in social flying, learning local airspace, and building the skills and relationships needed for eventual breeding.

A building-dependent species

Swifts nest almost exclusively in roof eaves, holes in walls, and cliff faces — habitats dramatically reduced by modern building practices. Sealed eaves and insulated walls have eliminated most traditional nesting sites. Swift boxes installed under eaves have become an important conservation measure.