One proposed explanation for pigeons' magnetic sense is that their inner ears act as tiny voltage generators. When a bird turns its head through Earth's magnetic field, the motion could induce small electrical signals. A new theoretical study, however, identifies a major obstacle: noise.
The study finds that background electrical noise in the inner ear would be far larger than any signal produced by head rotations. As a result, the tiny voltages would be buried in the noise and impossible to distinguish. This would make the mechanism ineffective for orientation, even if the physical principle holds.
The finding does not disprove magnetic sensing in pigeons, but it weakens the case for an inner-ear compass. The hypothesis remains speculative until researchers can show how the bird might overcome this noise barrier.