New research published in the journal Science indicates that humans are not alone in experiencing jet lag. A seabird species called the Manx shearwater appears to become mildly disoriented during extended flights over the Atlantic Ocean, according to the study. The authors attribute this confusion to the bird's internal clock drifting out of alignment with the sun's position in the sky.
Manx shearwaters are widespread in the British Isles. They resemble seagulls in appearance, but Patrick Lewin, a behavioral ecologist at the University of Oxford, noted that the species is actually a close relative of the albatross. The birds mate for life, and each breeding pair produces a single egg.
Parents alternate incubation duties. As Lewin explained to NPR Topics: National, one partner remains on the egg continuously while the other heads out to sea. For as long as two weeks, the foraging partner searches the North Atlantic for fish and squid, frequently ranging hundreds of miles from the nest. Once the bird has eaten its fill, Lewin told NPR Topics: National, "they absolutely bomb it back to their colony." The return trip often takes only a day or so.
That behavior prompted a question: do Manx shearwaters experience jet lag, or perhaps a form of flap lag? To investigate, Lewin drew on a remarkable dataset. For 20 years, his colleagues had fitted the birds with GPS trackers and gathered records of their outbound and return flights across the Atlantic. Because Manx shearwaters are thought to navigate by the sun, Lewin reasoned that the tracking data would reveal any jet lag in their routes.
Lewin explained to NPR Topics: National that using the sun as a compass requires knowing the time of day. In the morning the sun lies to the east, near midday it sits slightly to the south in the northern hemisphere, and by evening it has moved west. A bird with the wrong sense of time would therefore fly in the wrong direction.
That is precisely what the researchers observed. As the birds hurried back toward their mates and eggs, they drifted slightly off course. The effect was modest: the largest deviation recorded was seven degrees, which pushed a bird only about three miles off its path on a 600-mile journey. Lewin told NPR Topics: National, "It's a really small addition."
Alice Boyle, a biologist at the Centre for Animals on the Move at Western University in Ontario, Canada, who was not involved in the research, told NPR Topics: National that the paper is highly impressive. Boyle observed that nearly every organism on Earth, from corals to chipmunks, must find its way through its surroundings, yet studies capturing navigation decisions as they happen are uncommon. In her view, that rarity is what makes this GPS-based work so valuable. She told NPR Topics: National, "It's using these wild birds that travel to completely remote places and we're able to learn so much about how they do that."
