Five teams of people (more than 450 people, including 17 pilots and 14 cinematographers) were necessary to follow a variety of bird migrations through forty countries and each of the seven continents. The film covers landscapes that range from the Eiffel Tower and Monument Valley to the remote reaches of the Arctic and the Amazon. All manner of man-made machines were employed, including planes, gliders, helicopters, and balloons, and numerous innovative techniques and ingeniously designed cameras were utilized to allow the filmmakers to fly alongside, above, below and in front of their subjects.