A scientific study, conducted by an international team of researchers, has discovered a new clue as to how birds can migrate long distances over land and sea. Studying robins held the key. The research team found out how the small songbirds can sense the Earth’s magnetic field, and use it to navigate their migration route, through a chemical in their eye.
This discovery might be a breakthrough in understanding how birds migrate.
It is theorised that birds possess an in-built compass that, like a regular compass, helps them orientate in their surroundings. The new study might prove this theory by its discovery of the chemical in the robin’s eye.
The chemical, known as a cryptochrome, is sensitive to magnetism and light and therefore may allow birds to ‘see’ Earth’s magnetic field. It is a molecule located in the retina part of the eye.
“We think we may have identified the molecule that allows small migratory songbirds to detect the direction of the Earth’s magnetic field, which they undoubtedly can do, and use that information to help them navigate when they migrate thousands of kilometres,” says Peter Hore, Professor of Chemistry at the University of Oxford.
The international research team studied the molecule in their laboratory to see if it functions as a magnetic compass for birds. They found out that the molecule had the ability to form pairs of ‘radicals’, each consisting of other molecules and atoms that have a high magnetic sensitivity. The magnetically sensitive chemical reactions are initiated by light shining on the bird’s retina.
“It looks possible – and I would put it no stronger than that at the moment – that these highly-specialised chemical reactions could give the bird information about the direction of the Earth’s magnetic field and in that way constitute a magnetic compass,” Professor Hore explains.
Despite these new scientific findings, the research team cautions that there is a lot more work to be done before they can be sure they have found the correct mechanism and molecule.
Robins usually migrate across Europe during the nighttime, looking for warmer climates after spending their winter in Britain. They use the light of stars, the moon, and the sun during dusk and dawn to navigate their way to new areas containing food and shelter resources.