大象传媒

No one fully understands how an osprey's urge to fly south works, but suddnely it weakens and switches off. Adults will fly north next spring to start a new family, but youngsters will call this home for a year and a half until they mature. Only then will they make the return journey from Columbia to Martha's Vineyard in the USA and find a mate. They'll base their journey on the mental map they created on the 3,000 mile journey south. An osprey will follow exactly the same path when it flies north again, picking up on the same landmarks it used on the way down. They will make this journey again and again, for the rest of their lives.