Geomagnetic disturbance associated with increased vagrancy in migratory landbirds

Abstract

Abstract Summary:

Overview

Rare birds, often termed as "accidentals" or "vagrants," intrigue both birdwatchers and biologists. The causes of such rare occurrences are still not well understood.

Findings

• Migratory birds rely on the Earth's magnetic field, detected by specialized magnetoreceptor structures, for navigation across extensive, often unknown terrains.
• Disruptions in these magnetoreceptors or the magnetic field itself can lead to navigation errors, resulting in avian vagrancy.
• This study analyzed data from over 2 million captures of 152 different species of landbirds in North America across six decades.
• A strong correlation was found between disturbances in the Earth's magnetic field and increased vagrancy during the fall migration period.
• Interestingly, increased solar activity, which can disrupt avian magnetoreceptors, appears to counteract these disturbances, potentially decreasing the chances of misorientation.

Conclusion

The study establishes a probable link between geomagnetic disturbances and avian vagrancy, emphasizing the critical role of magnetoreception in bird orientation. These disturbances may have significant ecological effects, possibly affecting mortality rates among vagrants or aiding in the expansion of avian populations and their associated dispersers.