Can seabirds really get jet-lagged — and how does it bend their compass?

A new study in Science on Manx shearwaters — pigeon-sized seabirds flying hundreds of kilometres a day over the North Atlantic — found the birds jet-lag themselves on long feeding trips, and because they navigate by the Sun using an internal clock, the lag measurably skews their compass heading home. A true, sourced science story, plus what the same clock logic means for your own jet lag.

Short answer: yes — Manx shearwaters really can jet-lag themselves, and a new study published in Science shows the lag measurably bends the compass they steer by on the flight home. These are pigeon-sized seabirds that range hundreds of kilometres a day over the North Atlantic on feeding trips, then navigate back to breeding colonies around the UK and Ireland — about half the population breeds in Wales.How the trick works, in plain English: shearwaters steer by the Sun, but the Sun is only useful as a compass if you know the time. A bird reads the Sun’s position, checks it against an internal clock that says what time of day it should be, and works out direction from the difference.

On a long feeding trip the bird’s clock drifts out of step — the same lag you feel after a long flight — so on the way home it reads the Sun as if it were a different time, and its heading shifts by a matching amount. The researchers found that skew in the birds’ real homeward tracks: tired clocks, bent compasses.The concrete picture:1. The travellers: Manx shearwaters, small oceanic birds making feeding trips of hundreds of kilometres from their Welsh and Irish colonies.2.

The instrument: a Sun compass corrected by an internal body clock — elegant, and completely dependent on that clock being right.3. The finding: after long trips, clock lag skewed homeward headings by a measurable amount — jet lag with a compass error attached, in a bird that has never seen an airport.Pro tip for human readers: it is the same clock logic behind the standard jet-lag advice — shift your light exposure toward your destination’s schedule before a long flight, and your internal clock arrives closer to local time, so you read your own day correctly sooner.