New Delhi: Birds can experience jet lag while travelling long distances, according to a new study in the journal Science Advances. The study, conducted by scientists from the University of Oxford and published on 29 October, also found that this ‘jet lag’ leads to navigational errors in birds, since their natural cues are thrown off.

The study analysed the behaviour of Manx shearwater birds, which travel across longitudes every year. As seabirds, they fly close to the sea surface and travel east or west during homing, breeding, and seasonal changes. This means that they inevitably cross different time zones, which experience sunrise and sunset at different times.

“Most bird species that move huge distances travel latitudinally, avoiding such effects, but some species do move large east-west distances. Do these species experience mismatches in time?” asked the study.

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Sun compass errors

The researchers analysed 1,045 birds using GPS tracking systems during their routine travel of more than 1,000 km between their feeding grounds in the Northeast Atlantic and breeding colonies in the United Kingdom.

According to the study, they found that the birds had navigational difficulties and deviations on their route, which were consistent with ‘Sun-compass errors.’

This means that the birds used the position of the Sun as their navigational system while flying; however, as they crossed time zones, this system got disrupted. The study said that the behaviour of the birds’ internal clocks was similar to what humans experience during long-distance travel, which is commonly known as jet lag.

Based on living beings’ internal clocks, the scientists were able to predict how a bird would behave if changes in the time zone disrupted its navigational system. A bird travelling eastwards may experience a clockwise deviation from its intended direction, while one travelling westwards may move counterclockwise. These are predictable errors arising from the mismatch between the bird’s internal clock and the Sun’s actual position.

When they observed the Manx shearwaters during travel, they observed patterns in their deviation that were very similar to their prediction — confirming the theory that the birds relied on the Sun for their navigation, and changes in the Sun’s position led to this navigational system veering off course too.

The study also looked at the routes taken by these birds during their travel to understand if there were other navigational cues they could rely on, such as landmarks or coastlines. They found that yes, these alternate navigational cues did exist on their route.

However, the birds continued to rely on the Sun’s position for their navigation, even though it led to difficulties and challenges as they traversed time zones.

The study said that their findings indicate that a bird’s internal clock is crucial to help it navigate, but also that further research is required to understand how changing time zones affects other aspects of a living being’s internal functions.

(Edited by Ratan Priya)