For decades, we have heard many stories of pigeons being used as messengers. It was their precision that provided a strong amount of trust utilized in many situations, including stressful wars. There are incredible tales of bravery and accuracy with pigeons delivering messages during important times. We have covered a few tales within these pages. But we never wonder (much) about how these magnificent birds can do these incredible feats. There is a great deal of internal things that are occurring to provide these pigeons with their ability to be where they need to be, even after a long and trying trip through the airways of the world.

What we do know about pigeons is that they possess a remarkable sense of direction, like that of a GPS. They use the sun as a compass and can change directions as needed in relation to the movement of the sun. They can zero-in on a low-frequency sound that they remember. They also use, like many other birds during migration, the earth’s magnetic field to help guide them. You will certainly have no difficulty in investigating the ways that pigeons and other birds navigate this globe, going from place to place.

Could a Pigeon’s Liver Hold the Key to Navigation?

A recent study published in the journal, Science, suggests that pigeons must rely on other things when the skies are overcast to home in on their destination. Researchers recently discovered that the “superparamagnetic microphages” in their liver are likely the element that helps them to navigate. They arrived at this conclusion when pigeons who had flown in overcast conditions had a notable reduction in microphages in the liver. If the microphages were depleted, it seemingly made it impossible for the pigeon to get home during overcast surroundings.

So, what’s a “superparamagnetic microphage”? It is a cell in the liver that collects iron-oxide positive nanoparticles. Those nanoparticles are absorbed by blood proteins within the bloodstream and then delivered to the liver for nanoparticle ingestion. These iron-oxide particles then become strongly magnetized when they are in contact with an external magnetic field. In short, the tissue of the pigeon’s liver was infused with these microphages which are near hepatic nerve fibers of the pigeon. It is the Earth’s magnetic field that is interacting with magnetized microphages within the pigeon’s liver, thereby providing a new avenue of access to the magnetism of the field. When the sun is not there to guide them, they instinctively turn to the connection of their liver to the Earth to find their way home – hopefully before the microphages are depleted.

To further determine if the pigeon relied heavily on these internal microphages, researchers depleted the element and then sent the pigeon on a flight. For this research, 34 pigeons were trained to cover a region of 11.80 miles (19km). When cloudy skies were forecast, some of these pigeons were depleted of the microphages and others were not. The pigeons were affixed with internet-connected devices, which transmitted location. In every test, the microphage-rich pigeons completed their travels, while the pigeons with depleted microphages failed every time. Testing in ongoing to further get better information on the four existing theories of magnetoreception.

For the more adventurous reader who desires greater details on this, you can gain further insight from the Science journal here.