Birds may get bearings from beak sensors

OSLO (Reuters) - Birds may be able to fly vast distances without getting lost because of sensors in their beaks, according to a study on Wednesday.

German scientists said they found tiny iron oxide crystals in the skin lining of the upper beak of homing pigeons, laid out in a three-dimensional pattern that might help the birds to read the earth's magnetic field.

"The study suggests that the birds sense the magnetic field independent of their motion and posture and thus can identify their geographical position," publisher Springer said of the report in the journal Naturwissenschaften.

Scientists have long wondered how birds find their way, often migrating over thousands of miles to find the same tree.

"We expect that the pigeon-type receptor... might turn out to be a universal feature of all birds," according to author Gerta Fleissner and colleagues at the University of Frankfurt, writing in the journal Naturwissenschaften.

Similar iron-containing cells had been found in the beaks of robins, golden warblers and chickens, she wrote.