Every year, millions of migratory birds travel vast distances between breeding and wintering grounds. New experiments now suggest that pulsed radiofrequency magnetic fields could disorient them along the way — a result that sharpens our understanding of animal navigation.

In the study, published in the Journal of the Royal Society Interface, researchers exposed migratory songbirds to pulsed magnetic fields in the 1.41–1.5 MHz range. The birds subsequently lost the ability to orient using Earth's geomagnetic field. Crucially, the disruption appears to be mediated by a specialized sensory system rather than whole-body side effects.

A leading explanation for birds' magnetic sense is that magnetic fields subtly alter light-triggered chemical reactions inside a protein called cryptochrome in birds' eyes. The new results offer clues about how this chain, known as the radical-pair mechanism, actually works and where the interference takes hold.

The work by Kavokin and colleagues improves the understanding of the biological processes that let migratory birds find their bearings using the geomagnetic field — while raising fresh questions about how vulnerable that sense is to artificial electromagnetic fields.

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