New Theory on How Homing Pigeons Find Home

The birds could be using the specific sound signatures of home to navigate.

Homing pigeons (Columba livia) have been prized for their navigational abilities for thousands of years. They've served as messengers during war, as a means of long-distance communication, and as prized athletes in international races.

But there are places around the world that seem to confuse these birds—areas where they repeatedly vanish in the wrong direction or scatter on random headings rather than fly straight home, said Jon Hagstrum, a geophysicist who authored a study that may help researchers understand how homing pigeons navigate.

Hagstrum's paper, published online Wednesday in the Journal of Experimental Biology, proposes an intriguing theory for homing pigeon disorientation—that the birds are following ultralow frequency sounds back towards their lofts and that disruptions in their ability to "hear" home is what screws them up.

Called infrasound, these sound waves propagate at frequencies well below the range audible to people, but pigeons can pick them up, said Hagstrum, who works at the U.S. Geological Survey in Menlo Park, California.

"They're using sound to image the terrain [surrounding] their loft," he said. "It's like us visually recognizing our house using our eyes."Homeward Bound?

For years, scientists have struggled to explain carrier pigeons' directional challenges in certain areas, known as release-site biases.

This "map" issue, or a pigeon's ability to tell where it is in relation to where it wants to go, is different from the bird's compass system, which tells it which direction it's headed in. (Learn about how other animals navigate.)

"We know a lot about pigeon compass systems, but what has been controversial, even to this day, has been their map [system]," said Cordula Mora, an animal behavior researcher at Bowling Green State University in Ohio who was not involved in the study.

Until now, the two main theories say that pigeons rely either on their sense of smell to find their way home or that they follow the Earth's magnetic field lines, she said.


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