An Oxford University study has found that Manx shearwaters can become severely disoriented when rapid eastward flights disturb their internal body clocks, producing navigation errors of hundreds of miles as they return to their coastal breeding colonies.
Researchers analysed tracking data from birds that forage over the Atlantic and commute back to colonies on the west coast of the UK. The data showed that some individuals arrived far from their home sites after trips in which their eastward travel appeared to shift the timing of their circadian rhythms relative to local time.
The team described the phenomenon as a form of jet lag: when the birds’ internal clocks get out of sync with the environment, their ability to orient and navigate accurately is compromised. According to the researchers, the timing mismatch can be large enough to displace birds by substantial distances during homing flights.
The findings add a new dimension to understanding seabird navigation, which has typically been studied in terms of cues such as landmarks, olfaction and the sun or stars. By highlighting the role of timekeeping in successful homing, the study suggests that internal biological clocks are critical to the accuracy of long-distance returns from foraging areas.
Scientists behind the work said the results could inform further research into how environmental changes and human activity might influence migratory and foraging behaviour. They noted that clarifying the interaction between circadian rhythms and navigational systems will be important for assessing risks to seabird populations and for designing effective conservation measures.
Further study will be needed to determine how widespread the effect is among other species and what factors — such as flight speed, direction of travel, or local environmental cues — make some birds more susceptible to clock disruption and consequent disorientation.