The big blue is the world's greatest wilderness, far from shore and many kilometres deep. It's a vast marine desert where there is little to eat and nowhere to hide. Yet it's home to some of the biggest and most spectacular creatures on earth. This episode reveals what it takes to survive in this savage and forbidding world. We witness feats of incredible endurance, moments of high drama and extraordinary acts of heart-wrenching self-sacrifice. Every animal in the big blue must find their own unique way to survive. Sperm whales have the largest brains in the world. They live for 80 years, and we are only now beginning to learn the extraordinary complexity of their language of clicks - thought to coordinate the whole family in everything from childcare to hunting. With special pressure-proof cameras, we witness record-breaking feats of endurance as they hunt for squid a kilometre down into the abyss. Only recently have we begun to solve the mystery of where baby turtles disappear to in their early years. They leave the crowded waters of the coast and head to the open ocean, where they use floating debris like logs as life rafts. Here they remain until adulthood, adrift on the high seas in relative safety away from coastal predators. Over half of all animals in the open ocean drift in currents. Jellyfish cross entire oceans feeding on whatever happens to tangle with their tentacles. The jelly-like Portuguese man-of-war can harness sail power to fish with its deadly tentacles. Sometimes there is a brief explosion of food in this marine desert, but ocean hunters must be fast to make the best of this bonanza. We witness super pods of up to 5,000 spinner dolphins racing to herd vast shoals of lanternfish, briefly caught at the surface where it is thought they spawn. New aerial footage reveals, for the first time, the truth to a centuries-old sailors' legend of the 'boiling seas' - the spectacular feeding frenzy of 90kg tuna and dolphins smashing through the lantern fish shoals turning the sea white with foam.

In this bird's-eye view of two continents, demoiselle cranes negotiate a dangerous Himalayan pass on their way to India while high-flying bar-headed geese take the fast track five miles above. In Rajasthan, vultures watch hunting tigers hoping for a meal and pigeons visit a temple dedicated solely to sacred rats. Pigeons are also our guide to the greatest gatherings of camels on Earth and learn to dodge buzzards around the battlements of Jodhpur Fort. 9,000 cranes overwinter in the most unlikely of spots - a barbed wire compound in the centre of a desert town. In Australia, rainbow lorikeets drop in on Sydney and patrol Australia's Gold Coast. In the outback, white cockatoos swirl in thousands and budgerigars pass Uluru (Ayers Rock) and gather in the biggest flocks ever recorded. In China, swallows and swifts visit the Great Wall and the Forbidden City of Beijing. In Japan, the country's most revered birds - Japanese cranes are fed fish by appreciative locals and are joined in strange, momentary harmony by hungry red foxes, white-tailed eagles and Steller's eagles. As peace descends, Japanese cranes dance beautifully in the snow.

The documentary series 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. It is a journey that includes Machu Picchu, the Nasca Lines and the cities of Rio de Janeiro and Santiago. In Patagonia, giant petrels shadow killer whales as they hunt seals by stranding their huge bodies on the beach. At Iguassu Falls, dusky swifts dive through the cascades to huddle in communal roosts while hummingbirds bathe below. 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-metre cliff, as flight school begins. Deep in the Amazon, macaws seek medicinal clay. They are joined by a host of secretive jungle animals, including spider monkeys and tapirs, all after the same remedy. In Peru, condors soar over fighting sea lions waiting for causalities and on a mass exodus north, birds converge on the Panama Canal. 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.

Earthflight departs on its grand European tour, using a host of techniques including taking extraordinary footage from microlites as they fly alongside imprinted birds. Among other wonders, cameras soar with cranes and geese over Venice, the white cliffs of Dover and Edinburgh. White storks leave Africa and struggle to reach Istanbul, the gateway to Europe, while cranes take an easier route over the monkey-guarded Rock of Gibraltar. In France, the white horses of the Camargue make a splash around the new arrivals. In Rome, the heat of the city lures 20 million starlings that perform nature's greatest aerial display to outwit peregrines. In Hungary, sand martins grab mayflies from the air; and at Bass Rock, gannets create Britain's greatest natural spectacle as they dive in exquisite slow-motion. The story takes an emotional turn as storks and swallows wait for their partners to return and indulge in a spot of DIY to impress. Finally, geese touch down in Svalbard to raise a family. To protect their young, a squadron of birds assemble to see off polar bears. With views of birds flying over the Loire Valley, London docklands and the bulb fieds of Holland, this is Europe as never before.

Fly over Africa on the back of a vulture and see the most animal-packed continent with fresh eyes. Arrow-dive with cape gannets among sharks, dolphins and whales as they join the great sardine run. Soar with fish eagles as they discover an S-shaped living island comprised entirely of flamingos, and join them on a spectacular hunt. Fly with kelp gulls as they study the hunting behaviour of the greatest underwater predator of all: the great white shark. On the wings of eagles, fly through the mist-filled Victoria Falls and dive for fish in the mighty Zambezi. Circle with vultures high above the Serengeti as they watch the drama of the wildebeest migration below, and discover what happens when this canny scavenger suddenly becomes prey. Among toxic soda lakes, find out what it is like to be a flamingo, vulnerable to every predator on the continent, including baboons and hyenas. Join these flamingos as they take part in one of the most beautiful dances in the bird world. This is Africa as never seen before - from the wings of birds

A bird's-eye view of some of the world's greatest natural spectacles. Amazing sights from five continents are revealed in a whole new light. Using cutting edge new filming techniques to show everything in exquisite detail, viewers have a uniquely privileged perspective. The first episode takes flight across North America, as a flock of millions of snow geese discover what it is like to be on the hit list of America's national bird: the bald eagle. In California, pelicans reveal devil rays that perform astonishing somersaults and find bizarre grunion fish that wriggle ashore to spawn. In Alaska, bald eagles swoop among brown bears fishing for salmon. And on the Great Plains, cowbirds duck and dive under the feet of fighting bison.