The Bird That Never Lands: How Common Swifts Fly for 10 Months Straight

One-sentence takeaway: The common swift (Apus apus) is the most aerial creature on Earth — a 2016 Lund University study showed individuals can fly for up to 10 months without landing, eating, drinking, mating, and even sleeping on the wing.

How do we know it's 10 months?

In 2016, researchers at Lund University in Sweden published a landmark study: they fitted common swifts with tiny back-mounted data loggers and tracked them across a full year of migration. The result stunned ornithologists — some individuals flew for ten straight months without touching down once.

The details are even more extreme: one swift landed on just four nights during an entire winter. The following year, it stopped for only two hours. For these birds, landing is a luxury reserved for the breeding season.

Life on the wing

Swifts have taken aerial living to its logical extreme — every survival need has a "flight version":

• Eating: They catch flying insects, spiders, and termites mid-air, snapping them up without missing a wingbeat.
• Drinking: They skim ponds and lakes, dipping their beaks without ever stopping.
• Mating: It happens in the air! Males and females chase each other at high speed, lock mid-sky, and mate — courtship, pairing, and copulation all occur without touching the ground.
• Sleeping: They use unihemispheric slow-wave sleep — half the brain rests while the other half keeps flying, navigating, and avoiding predators. At dawn and dusk they climb to ~3,000 meters and glide down while catching micro-naps, like pilots alternating shifts on a trans-Atlantic flight.

Its name literally means "no feet"

The genus name Apus comes from Greek for "without feet" — and that's physical reality, not poetry. Swifts' legs are so short they cannot walk, and they can't perch on wires like swallows. They cling to vertical walls with tiny feet like grappling hooks, then push off and drop back into the sky. On flat ground, they're helpless — they can't even take off.

Young swifts leave the nest and fly for two to three years without ever landing, until they return to breed. A swift can live up to 20 years, spending nearly its entire existence in the air — when it finally dies of old age, it likely falls from the sky.

A machine built for flight

• Single-day range: over 800 km; annual migration over 10,000 km.
• Level-flight speed: close to 110 km/h — faster than any other bird under its own power.
• "Screaming parties" — high-speed mating chases — are a signature of summer evenings in cities across Europe and Asia.

Swift vs. swallow: how to tell them apart

The easiest distinction: look at the wings and tail. Swifts have long, sickle-shaped wings and short, barely forked tails — they fly like boomerangs in the sky. Swallows have deeply forked "scissor" tails and regularly perch on wires — swifts never do. If you see a "swift" sitting on a power line, it's a swallow.

Where to watch them

Swifts are urban specialists: on summer evenings, look up near tall buildings and church towers for fast-circling, sickle-winged birds with piercing calls. They nest in building crevices and towers — among the few truly wild species that have adapted completely to cities. The key observation: they are always flying.

FAQ

Q1: Do swifts really sleep while flying?

A: Yes. They use unihemispheric slow-wave sleep (USWS) — one brain hemisphere rests while the other keeps flying and navigating, in micro-naps of seconds to minutes that add up to real rest.

Q2: What's the difference between a swift and a swallow?

A: Swifts (Apus apus) have sickle-shaped wings, short tails, and legs too short to perch on wires — they're almost never grounded. Swallows have deeply forked tails and perch regularly; they belong to different families (Apodidae vs. Hirundinidae).

Q3: Why did swifts evolve to never land?

A: Because their legs are too short to take off from the ground — landing is effectively fatal. Flight is both their foraging strategy and their survival mechanism; "never landing" is an extreme adaptation to that evolutionary pressure.

Q4: How far do swifts fly in a year?

A: Over 10,000 km of migration annually, and more than 800 km in a single day. European swifts winter in southern Africa.

Q5: How long do swifts live?

A: Up to about 20 years in the wild — remarkably long for a small bird, largely because spending life airborne avoids most ground predators.