Scientists probe how pigeons use magnetism to navigate

Homing pigeons rely on a variety of signals to navigate, including magnetism. But it hasn't been clear how they detect magnetic cues. Researchers propose the answer may be found in the birds' livers. NPR Science LISTEN & FOLLOW Science Scientists probe how pigeons use magnetism to navigate June 4, 20264:13 PM ET Heard on All Things Considered Ari Daniel Scientists probe how pigeons use magnetism to navigate Listen · Transcript Toggle more options Download Embed Embed <iframe src="https://www. npr. org/player/embed/nx-s1-5845078/nx-s1-9797811" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player"> Transcript Homing pigeons rely on a variety of signals to navigate, including magnetism. But it hasn't been clear how they detect magnetic cues. Researchers propose the answer may be found in the birds' livers. SCOTT DETROW, HOST: Homing pigeons rely on a variety of signals to navigate the skies, including magnetism. But it's never been quite clear how exactly the birds detect magnetic cues. A team of researchers proposes the answer might be found in a pretty unexpected place. Here's science reporter Ari Daniel. ARI DANIEL: Drop a homing pigeon somewhere it's never been, and the bird can flap its way back home. MARTIN WIKELSKI: You have to provide them actually a good home so that they want to return, and that means good food and nice, cozy housing. DANIEL: To fly home, a pigeon has to figure out where it is and in which direction to go, says Martin Wikelski, who directs the Max Planck Institute of Animal Behavior in Germany. They rely on odor cues, the sun, visual landmarks and magnetic direction, which is using Earth's magnetic field to orient and navigate. WIKELSKI: It would be as if you were put into a forest where you know my home is east. And then you have a compass. You end up at your cabin. DANIEL: Pigeons rely on magnetic direction under certain circumstances. WIKELSKI: That is, either at night or during completely overcast conditions. DANIEL: For decades, researchers have struggled to explain how these pigeons sense magnetic direction. Then some years back, Wikelski was attending an interdisciplinary meeting where he met someone he might never have encountered otherwise - immunologist Christian Kurts from the University of Bonn in Germany. CHRISTIAN KURTS: And in the coffee break, we talked to each other. Show me one scientist who doesn't like talking about their research (laughter). DANIEL: Kurts told him he'd been studying immune cells called macrophages when he stumbled upon something surprising.