A new study by German researchers suggests that the remarkable ability of homing pigeons to find their way home over long distances may be linked to specialized cells in their liver that help them detect the Earth's magnetic field.
The research, conducted by scientists at the University of Bonn and the Max Planck Institute of Animal Behavior, sheds new light on one of the most enduring mysteries in animal navigation.
Homing pigeons, scientifically known as Columba livia, are renowned for their ability to return to their home locations from hundreds of kilometers away. Scientists have long believed that birds rely on a combination of environmental cues, including the sun, landmarks, and the Earth's magnetic field.
Previous studies identified potential navigation mechanisms in the birds’ beaks, eyes, and brains. However, the new research focuses on specialized immune cells in the liver known as superparamagnetic macrophages.
According to the researchers, these cells accumulate iron, making them potentially sensitive to magnetic fields and allowing them to contribute to the birds' magnetic sensing abilities.
During experiments, scientists reduced the number of these liver cells and observed the pigeons' behavior under different weather conditions. The birds showed difficulty determining their usual direction when flying under cloudy skies, where visual navigation cues were limited.
In contrast, pigeons continued to navigate successfully in clear weather, relying on the sun and visible landmarks to find their way.
The findings suggest that pigeons do not depend on a single navigation system but instead combine several sensory mechanisms to orient themselves. Researchers said the results provide evidence that the liver may play a previously overlooked role in magnetic navigation.
The study adds to growing scientific understanding of how migratory and homing animals perceive their environment and could open new avenues for research into biological magnetic sensing in birds and other species.