Manx shearwaters show measurable navigation errors after transatlantic flights

Patrick Lewin, a behavioral ecologist at the University of Oxford, has documented a specific form of disorientation in Manx shearwaters that mirrors human jet lag. The research, published in the journal Science, demonstrates that these seabirds become slightly misaligned when traveling long distances across the Atlantic Ocean. The authors attribute this shift to the birds' internal biological clocks falling out of sync with the actual position of the sun in the sky.

Manx shearwaters are common in the British Isles and share a close evolutionary lineage with albatrosses rather than seagulls, despite their similar appearance. These birds mate for life and lay a single egg during the breeding season. The pair divides incubation duties, with one partner staying on the nest while the other forages at sea. Hunting partners spend up to two weeks scavenging for fish and squid in the North Atlantic, often traveling hundreds of miles from their colonies.

Upon returning with full stomachs, the birds rush back to their partners and eggs, often completing the journey in a single day. This rapid transit raised a question for Lewin regarding whether the birds experience navigational lag similar to the condition humans suffer when crossing time zones. To test this hypothesis, Lewin utilized twenty years of data collected by his colleagues. The team had tagged the birds with GPS trackers to monitor their flight paths out to the Atlantic and back.

The analysis relies on the understanding that Manx shearwaters use the sun as a compass for navigation. This method requires the bird to accurately perceive the time of day. In the northern hemisphere, the sun moves from the east in the morning to the south at midday and then to the west in the evening. If a bird’s internal clock is incorrect, it will calculate the wrong heading. Lewin and his team observed that the birds veered slightly off course during their return flights.

The maximum deviation recorded was a seven-degree error. This small angular shift resulted in a bird straying by approximately three miles during a 600-mile journey. Lewin described the discrepancy as a really small addition to their travel path. The findings provide concrete evidence that these birds experience a physical consequence of rapid travel that affects their spatial orientation.

Alice Boyle, a biologist at the Centre for Animals on the Move at Western University in Ontario, Canada, praised the research. She was not part of the study but noted that navigation decisions are rarely observed in the wild. Boyle highlighted that most creatures, from corals to chipmunks, must navigate their environments. The GPS work allows scientists to learn how these wild birds operate in remote locations.

The study confirms that the internal clock mechanism affects navigation in species other than humans. The data shows a direct link between time perception and directional accuracy in long-distance flyers. The research adds to the understanding of how biological timing systems interact with environmental cues during rapid transit.