Atlantic puffins suffer from a phenomenon akin to human jet lag when they traverse the ocean quickly, according to research conducted by the University of Oxford. The study indicates that these birds' internal clocks become desynchronized from local time during rapid crossings, which disrupts their solar compass and causes them to deviate from their intended flight paths back to their nests.
Just as humans traveling across multiple time zones experience a mismatch between their circadian rhythm and the local environment, long-distance flying birds face similar challenges. The research focused on Atlantic puffins, seabirds capable of traveling up to 1,000 kilometers west from colonies off the coast of Great Britain in search of food. When these birds return, the rapid shift in longitude can throw their internal timing mechanisms out of sync with the actual position of the sun.
Birds often rely on the sun as a compass for orientation. A bird flying south must constantly adjust its heading because the sun appears on the left at sunrise and on the right at sunset. To manage this, animals utilize an internal clock that regulates activity and sleep cycles. Dr. Patrick Lewin, a researcher at Oxford's Department of Biology and lead author of the study published in Science, explained that this same biological mechanism is responsible for the observed navigation errors.
To investigate how these birds navigate over vast oceanic expanses, researchers analyzed 20 years of GPS data from 1,045 nesting Atlantic puffins. By calculating the expected navigational error based on the birds' positions and the sun's movement, assuming their internal clocks remained set to dawn time, the team found that the actual flight paths closely matched these predicted errors. Out of 335 return flights made out of sight of land, the headings followed by the birds aligned with the miscalculations caused by the time lag.
Dr. Lewin noted that the process causing this discrepancy between the internal clock and external time is identical to the mechanism behind human jet lag. While the study did not investigate whether this clock shift affects other behaviors beyond navigation, internal clocks also regulate feeding and resting patterns. Since puffins tend to hunt shortly after dawn and before dusk when prey is near the surface, a misaligned rest period could cause them to miss critical feeding opportunities.
Interestingly, the study showed that birds continued to rely on their solar compass even when other information sources were available. Along the coastlines, where familiar terrestrial landmarks could have guided them, the birds' distance from the shore still varied in the direction predicted by solar compass errors. Professor Tim Guilford of Oxford suggested that navigation typically involves a two-step process: a "map" phase to determine location relative to a destination, followed by a "compass" phase to translate that information into movement.
The researchers propose that birds may continue to combine these systems even in familiar areas rather than relying solely on one. Dr. Lewin suggested that if the resulting deviations are minor, there may not be strong evolutionary pressure against this behavior. Additionally, the solar compass might help birds determine direction along linear features like coastlines. Even cloud cover does not necessarily render the solar compass useless, as data suggests birds can perceive polarized light to estimate the sun's position unless the sky is heavily overcast.
While jet lag in humans is linked to short-term discomfort and long-term health issues for frequent travelers like pilots, it remains unknown if birds suffer similar consequences. However, species like puffins that regularly undertake long east-west journeys may have developed mechanisms to cope with repeated disruptions to their biological clocks. Dr. Lewin concluded that understanding this phenomenon is a first step, and these birds might eventually offer insights into how humans can better treat or avoid jet lag.
Sources: Le Figaro.