Seabirds that race across the Atlantic to reach their feeding grounds may be paying a hidden price for their speed: jet lag. A study led by the University of Oxford has found that Manx shearwaters flying long distances eastwards can experience a mismatch between their internal body clocks and local solar time, the same process that produces jet lag in humans, and that this mismatch causes them to make predictable errors when navigating by the sun. The results have been published in the journal Science.
Many animals, including birds, use the sun to find their way. But because the sun moves across the sky throughout the day, an animal relying on it as a compass needs an accurate internal clock to interpret its position correctly. Normally, birds reset their internal clocks using sunrise as a cue. When they travel rapidly east or west during the day, however, their internal clocks may temporarily fall out of sync with local solar time, which could cause them to misjudge the sun’s position and fly slightly off course.
To investigate whether this happens in the wild, researchers led by Oxford University’s Department of Biology analysed 20 years of GPS tracking data from 1,045 Manx shearwaters, covering 3,688 foraging trips. Manx shearwaters, known scientifically as Puffinus puffinus, breed on islands off the western coasts of the UK and Ireland. They regularly travel hundreds of kilometres out to sea in search of food, sometimes reaching feeding grounds around 1,000 km west of their breeding colonies.
The problem arises on the return journey. When heading back to their nests, the birds can travel rapidly eastwards across lines of longitude, moving into places where the sun rose earlier, just as humans do when they fly into earlier time zones. As a result, their internal clocks may lag behind local solar time by up to around one hour. A bird whose clock is running an hour behind will read the sun’s position in the sky as if it were an hour earlier in the day, and that misreading points the compass in the wrong direction.
The researchers found that the birds’ flight directions showed systematic deviations consistent with the predicted effects of these time shifts on their sun compass. As the birds travelled eastwards, they tended to deviate clockwise from their expected direction, exactly as would be predicted if their internal clocks were running behind local time. The team used statistical models to compare the observed deviations with those predicted from the birds’ movements and the changing position of the sun. The results supported the sun-compass explanation, which also fitted the data better than an alternative explanation based on changes in the Earth’s magnetic field.
Remarkably, the navigational errors persisted even when the birds were flying along visible coastlines, where landmarks could in principle have helped guide them. When the predicted compass error pointed towards land, the shearwaters tended to fly closer to the coast. When it pointed away from land, they tended to fly further out to sea. This suggests that the birds continued to rely on their sun compass even when other navigational cues were available, rather than simply following the coastline beneath them.
Lead researcher Dr Patrick Lewin of the Department of Biology at Oxford University said: “It’s amazing to think that billions of migratory animals look up to the sun for direction, relying on clocks silently ticking away inside them, and that errors in those clocks can cause them to take tiny shifts off course.” Co-author Professor Tim Guilford, also of the Department of Biology, added: “It’s inherently difficult to study the cognitive processes of animals in the wild, so it’s exciting to realise that if we measure their natural movements carefully enough we can reveal the underlying behavioural mechanisms.”
The errors themselves were relatively small, reaching approximately 15 degrees in the shearwaters studied. Because these birds appear able to reassess their position and adjust their route home continuously, the additional distance travelled is likely to be modest. The researchers calculated that a shearwater returning from 1,000 km away, with an average compass error of 7 degrees and continuously correcting its course, would travel only around 5 km further to reach within 5 km of its colony. For a bird that routinely covers such vast distances, the detour is barely noticeable.
The wider implications may be more significant for animals that travel long distances without being able to correct their position continuously. In birds undertaking their first migration, for example, small compass errors could potentially accumulate, shifting their eventual destination by hundreds of kilometres. Because internal clocks regulate many aspects of animal behaviour and physiology, the researchers suggest that similar time shifts could potentially have effects beyond navigation. In humans, travelling rapidly across time zones causes jet lag, a mismatch between the body’s internal clock and local time that can lead to disturbed sleep, fatigue and other symptoms. Further research is needed to establish whether similar effects occur in wild migrating birds and whether this has consequences for their health, behaviour or survival.
Dr Lewin added: “Our results show that animals experience the same internal clock mismatch as we do during jet lag. The next step is to understand how that affects them. Do they mistime critical behaviours? Do they experience physiological side effects like we do? And is this mismatch as damaging to their health as jet lag is to ours? Perhaps these birds that routinely travel long distances could help teach us how to cope with and treat jet lag to avoid the really negative effects it can have on our health.” The study, titled ‘Rapid longitudinal flights cause time shifts and sun compass error’, was published in Science on 29 October 2026, DOI 10.1126/science.adz2542.
Subject of Research: How rapid longitudinal flights desynchronise the internal clocks of Manx shearwaters and cause sun compass navigation errors
Article Title: Long-distance flights can throw seabirds' internal clocks out of sync, causing navigation errors
Article References: Long-distance flights can throw seabirds' internal clocks out of sync, causing navigation errors. Original publication (Bibliographic details unavailable.)
Image Credits: AI Generated
DOI: Not provided
Keywords: Manx shearwater, sun compass, internal clock, jet lag, navigation, GPS tracking, animal migration, Oxford University, Science journal, time shifts, seabirds, compass error
News Source: Drew Townsend. (October 30, 2026). Seabirds Flying Across Time Zones Get Jet Lag That Steers Them Off Course. Scienmag.
