The Screaming Arrows Are Back
Image: Alexis Lours, CC
There's a sound that means summer has truly arrived in Hannover: a high-pitched, piercing shriek cutting across the rooftops, followed by a dark crescent shape tearing past at improbable speed. The swifts have returned. They came back this morning, wheeling in loops in and above our courtyard.
If you don't know how a swift looks: They look somewhat like swallows and are sometimes confused with them. Swifts are a bit larger, with very long, scythe-like wings and a short forked tail — in silhouette they look almost like a flying anchor. But good luck identifying a common swift accurately – they are simply too fast. That's why I can't present an own image here. No way making a good image with my smartphone.
The best way to differentiate them is the flight style: Swallows seem to move around in little hops, mostly alone, whereas Swifts are like fighter jets, screaming as they go, as if outrunning something. Sometimes they form small groups and fly together. Those groups have a name: screaming parties.
What I find especially fascinating and what makes swifts genuinely extraordinary is that outside of breeding, they never voluntarily touch the ground. They eat in the air, drink by skimming water surfaces, collect nesting material on the wing, and even mate in flight. Young swifts that fledge from their nest holes won't land again for two to three years. When researchers tracked swifts with tiny data loggers, they confirmed what had long been suspected: swifts sleep in the air too, rising high at dusk and entering a state of unihemispheric slow-wave sleep — resting one half of the brain at a time while the other keeps them aloft and navigating. The only time this animal is still is when it's sitting on eggs or chicks in its nest cavity.
By the time they arrived today, they had already flown around 20,000 kilometres — they migrate from European breeding grounds down to sub-Saharan Africa and back. Over its lifetime of around five to eight years (some individuals reach sixteen), a swift may fly more than two million kilometres.
For now though, they're back above the courtyard, screaming their heads off. There are worse ways to start a Sunday morning. By late July or early August, marking the unofficial end of summer for me, they'll be gone again.