America’s majestic national bird was close to extinction when Tina Morris, a young researcher, was asked to help bring three chicks to adulthood. First, she had to conquer a fear of heights

It was a daunting task, with little likelihood of success. An adventurous but anxious graduate researcher without any experience of looking after birds was dispatched to the wilds of upstate New York to become a human eagle mother: feeding, teaching – and keeping alive – three helpless eagle chicks.

Tina Morris was to camp alone beside their artificial nest, find them food, track them when they began to fly, keep them away from danger and rescue them if they got into trouble. If they survived to adulthood, northwest America would begin to be repopulated with its national bird, the bald eagle, a majestic, much-loved raptor that had been driven to the brink of extinction by the 1960s.