Transcript

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NARRATOR:

Ospreys are not only masters of the air ... but of the sea as well.

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Every year, they take part in an extraordinary migration of around 6000 miles between the perfect nesting sites in the north and the best fishing - way, way south. Our journey begins north of New York, in Martha's Vineyard. Sixty-five pairs of ospreys breed on this little island - and they're all about to leave.

Osprey biologist Rob Bierregaard has been studying their migration for the last five years. He attaches little solar-powered transmitters to wild ospreys. Via satellites, they beam the birds' location back to him, so he can see where they are, anywhere on the planet.