Iron-Rich Immune Cells Found in Homing Pigeons’ Livers May Contribute to Magnetic Sensing

A new paper has identified iron-rich immune cells in homing pigeons' livers as the likely source of the birds' magnetic compass. The finding offers a concrete cellular mechanism for how homing pigeons detect Earth's magnetic field and use its directionality to navigate. The same cells appear absent or less prominent in species whose navigation does not rely on magnetism to the same degree.

Researchers examined liver tissue from homing pigeons and documented clusters of immune cells containing high concentrations of iron. Migratory songbirds and sea turtles also detect Earth's magnetic field and use its directionality to navigate, according to established observations in multiple species.

The pigeon study supplies one of the first direct cellular candidates for the underlying sensory structure.

@ScienceMagazine reported the paper's central claim that iron-rich immune cells within homing pigeons' livers provide the magnetic compass. The report noted that the cells' iron content and location distinguish them from previously examined magnetoreceptor candidates in the beak or inner ear. No other organ or cell type showed comparable iron enrichment in the sampled pigeons.

The paper stops short of claiming the same cells operate in songbirds or sea turtles, leaving cross-species tests for future work.