S1, E4: Earthflight gives a bird's-eye view of South America, as condors soar along the Andes, scarlet macaws explore the heart of the Amazon and hummingbirds and vultures see the continent's greatest sights. In Patagonia, giant petrels shadow killer whales as they hunt seals by stranding their huge bodies on the beach. In a secret Andean location, condors soar in flocks over 40-strong and scavenge on casualties from herds of fighting guanacos. Elsewhere, a mother condor gently pushes her youngster to the edge of a 200-meter cliff, as flight school begins. Deep in the Amazon, macaws seek medicinal clay. In Costa Rica, black vultures descend on turtles as they lay their eggs in the sand and pick off the eggs that ping-pong through the air.