When migrating birds go astray, disturbances in magnetic field may be partly to blame

Disturbances to Earth’s magnetic field can lead birds astray — a phenomenon scientists call ‘vagrancy’ — even in perfect weather, and especially during fall migration. While other factors such as weather likely play bigger roles in causing vagrancy, researchers found a strong correlation between birds that were captured far outside of their expected range and the geomagnetic disturbances that occurred during both fall and spring migrations.