Natures wonders: magnetic field migration (Introduction)

by David Turell , Wednesday, October 14, 2015, 18:27 (3326 days ago) @ David Turell

That is all that is needed for migratory birds to fly home:-http://www.scientificamerican.com/podcast/episode/magnetic-field-may-be-a-map-for-migratory-birds/?WT.mc_id=SA_MB_20151014-"If you're lost, you need a map and a compass. The map pinpoints where you are, and the compass orients you in the right direction. Migratory birds, on the other hand, can traverse entire hemispheres and end up just a couple miles from where they bred last year, using their senses alone. Their compass is the sun, the stars and the Earth's magnetic field. But their map is a little more mysterious. One theory goes that they use olfactory cues—how a place smells. Another is that they rely on their sense of magnetism.-"Researchers in Russia investigated the map issue in a past study by capturing Eurasian reed warblers on the Baltic Sea as they flew northeast towards their breeding grounds near Saint Petersburg. They moved the birds 600 miles east, near Moscow. And the birds just reoriented themselves to the northwest—correctly determining their new position.-"Now the same scientists have repeated that experiment—only this time, they didn't move the birds at all. They just put them in cages that simulated the magnetic field of Moscow, while still allowing the birds to experience the sun, stars and smells of the Baltic. Once again, the birds re-oriented themselves to the northwest—suggesting that the magnetic field alone—regardless of smells or other cues, is enough to alter the birds' mental map."-Comment: And we need GPS!