Pigeons Use Their Livers to Find Their Way Home

The new study looked at special cells called macrophages in the pigeons' livers. These cells are part of the birds' immune system and normally break down old red blood cells. When they do this job, the cells collect iron from the blood. Scientists think this iron helps the cells sense magnetic fields, like tiny compasses inside the pigeons' bodies.

To test their idea, the researchers removed these special cells from some pigeons. Then they watched how well the birds could navigate on cloudy days when the sun wasn't visible. The pigeons without these liver cells got lost and couldn't find their way home. However, when the sun was shining, the same birds could navigate just fine using visual clues.

The scientists were surprised by their discovery. Martin Wikelski, a director at the Max Planck Institute, said that what looks like a 'gut feeling' in bird navigation may actually have a physical basis. The immune cells are located near nerve cells in the liver, which may be how they send information to the pigeons' brains.

Christian Kurts, another scientist who worked on the study, explained their shock at the results. 'We didn't expect immune cells to act like sensors for magnetic fields at all,' he said. The team knew that livers and spleens might be important because these organs store lots of iron when they break down red blood cells.

Humans have used pigeons' amazing navigation skills for thousands of years. Ancient Greeks used pigeons to carry news about Olympic winners and battle victories. The Romans used pigeon networks to send messages across their huge empire. Even during World Wars I and II, armies used pigeons to carry important messages from the battlefield back to headquarters. In World War II, Britain dropped over 16,000 pigeons into occupied France to gather information about enemy troops and send it back home.