Jet Lag Disrupts Navigation in Foraging Manx Shearwaters
Oxford study reveals how internal clock desynchronization impacts migratory bird navigation accuracy.
1Biological Clock and Navigation
Manx shearwaters rely heavily on the sun as a primary compass for long-distance navigation. Because the sun shifts position as the Earth rotates, these birds must synchronize their internal body clocks with local time. This study investigates how rapid eastward flights disrupt this synchronization, effectively causing a form of avian jet lag.
2Twenty Years of Tracking
Dr. Patrick Lewin and his colleagues at the University of Oxford analyzed two decades of GPS tracking data from wild birds. This research moves beyond traditional laboratory settings to observe how shearwaters behave in their natural environment. The data specifically highlights navigation patterns during return flights across various lines of longitude.
3Impact on Adult Birds
Adult shearwaters demonstrate a remarkable ability to correct their bearings while in flight. Even when their internal clocks lag by approximately one hour, they only veer off course by about 15 degrees. This minimal deviation adds roughly 3 miles to a 600-mile journey, showing that experienced birds possess effective compensatory mechanisms.
4Vulnerability of Inexperienced Foragers
The study identifies a significant disparity between adult birds and first-time foragers. While adults can reorient themselves, inexperienced birds lack the necessary map sense to correct course errors. Consequently, these younger birds are at a much higher risk of flying hundreds of miles off course during their initial migratory return trips.
5Sun Compass Mechanism Failure
The birds' reliance on the sun compass creates a specific vulnerability when local time and internal clocks mismatch. When the sun appears farther across the sky than expected, the birds drift from their intended path. This error persists even when birds follow coastlines, suggesting the sun remains their primary navigational anchor.
6Evidence from Coastal Landmarks
Surprisingly, the navigation errors remained consistent even when birds followed recognizable coastlines. This finding reinforces the theory that the sun compass plays a central role in their orientation, overriding visual landmarks. The data suggests that internal timing is a more critical factor for these birds than previously understood in wild settings.
7Expert Perspective on Findings
Prof. Richard Holland of Bangor University notes that this study confirms findings from controlled experiments within wild animal populations. While the consequences of these small errors for returning birds remain unclear, the research underscores the vital importance of biological rhythms in managing complex animal behaviors across various ecological and migratory contexts.
8Broader Implications for Biology
This research highlights the necessity of understanding biological rhythms across multiple environmental contexts. As scientists continue to map these behaviors, the role of internal clocks in animal survival becomes increasingly evident. Future studies may further clarify how these navigational shifts impact the long-term fitness and survival rates of migratory seabird populations.
Original article: Science | The Guardian — Jet Lag Disrupts Navigation in Foraging Manx Shearwaters