"One 150 million years ago, as dinosaurs approached their golden age, one group evolved along new and revolutionary lines." "Although they retained many of their reptilian characteristics, they acquired extraordinary new ones... feathers." "Feathers helped with insulation and display." "But they offered something far more valuable." "The power of flight." "And for birds, that changed everything." "Birds have the freedom of the skies, to travel further and faster than any other group of animals and to seize opportunities in all corners of the planet." "But this freedom brings many survival challenges, which birds must tackle at pivotal moments in their lives." "Flying demands enormous skill and effort, and nowhere is that more evident than here, in the foothills of the Peruvian Andes." "This female hummingbird hovers with precision in her quest for nectar." "Herwing and tail design allow her to fly in any direction." "But the male has a real problem flying." "And this is why he's weighed down with two super-long tail feathers, tipped with cumbersome discs." "This is the marvellous spatuletail hummingbird and these are his flags with which to seduce a mate." "Waving them back and forth takes a lot of effort, even from the comfort of his perch, but to win her heart he's got to go up a gear." "He must show her how well he can fly but it's exhausting work." "It's so demanding he can only stay airborne for a matter of seconds before he needs a rest." "He's struggling to impress her, so one last try." "The extreme effort and energy needed to hover means hummingbirds can only fly in short, sharp bursts." "But most birds need to stay airborne for considerably longer, and must find far more energy-efficientways to get around." "Here in the Simien mountains of Ethiopia, at a breathtaking altitude of 15,000 feet, lives a supreme aerial maestro." "The lammergeier." "This youngster glides on air currents rising from the mountain slopes below." "His nine-foot wingspan can carry him hundreds of miles a day in search of animal carcasses, with precious little effort." "He watches out for other airborne scavengers, like these griffon vultures." "They lead him to some commotion on the cliffs, and maybe the chance to feed." "But this youngster is not the only lammergeier to spot the opportunity." "So too has this adult." "The vultures quickly strip the carcass clean." "It seems he's too late." "But in fact he's timed his arrival perfectly." "There's no meat left and that's exactly the moment that the lammergeier has been waiting for." "It's bones he's after." "The young lammergeier too homes in on the carcass." "Bones contain rich marrow fat, but extracting it is not easy, especially when the bone is a solid four kilos and too big to swallow." "But lammergeiers have an extraordinary solution, thanks to their flying skills." "Soaring up on thermal air currents and positioning the bone parallel to his body to minimize drag, he soon reaches the perfect height." "From here he glides to a place he knows where he can deal with the bone, where there are giant rock slabs sit on the lip of an escarpment." "The bone is smashed." "The juices in his stomach are more corrosive than battery acid." "They dissolve the bone so that he can now digest the marrow." "Others come looking for leftovers." "But their timing isn't ideal because now the young lammergeier has his turn!" "They'd better mind their heads!" "Proficient bone smashing takes endless practice to findjust the right height, speed and moment of release." "Lammergeiers have long, broad wings, ideal for gliding great distances with maximum efficiency." "But on the island of Little Tobago in the Caribbean lives a bird forwhom aerial agility is of paramount importance." "The red-billed tropicbird." "Short, pointed wings give it great manoeuvrability and speed." "During the breeding season, these flying skills are tested to the limit." "While one parent looks after the chick, the other mustjourney far offshore, to gather small fish and squid from the surface waters." "But the hardest part is getting food back to the island, because they share this airspace with thieves." "Magnificent frigatebirds, known as Man O' War birds, patrol high above." "These pirates are not trying to kill the tropicbird, but force it to give up its catch." "It's an aerial dogfight." "Tropicbirds are quicker on the turn." "Frigates have exceptionally lightweight bodies and their extremely long wings give them great power." "Success." "A favourite attack is from behind, and at height." "There goes the fish - another victory." "This tropicbird chick still awaits the return of its parent who has yet to run the gauntlet of the pirates." "Keeping close to the waves is his best chance." "Frigatebirds have so little oil in their feathers they can't risk ditching." "If he canjust reach the cliffs he'll be safe." "He's made it, with his crop still full of fish." "Red-billed tropicbirds rely on extreme aerial agility to overcome the many challenges of their life." "For others, survival demands endurance." "Every spring, red knots fly 10,000 miles from their wintering grounds in Argentina to their nesting sites in Canada." "The only way they complete this marathon journey is by making a crucial fuel stop here in Delaware Bay, on the east coast of America." "What is most extraordinary is that as well as having to find their way to this one location, they must also time their arrival to perfection." "They have a rendezvous with prehistoric creatures emerging from the deep which have hardly changed in 250 million years." "They come ashore in greatest numbers on the highest spring tides." "Horseshoe crabs." "The crabs are here to lay their eggs." "That's what the knots are after." "Most eggs are buried out of reach, but some are accidentally dug up by other crabs." "Most of the west Atlantic red knot populationjoin this feeding frenzy." "In a matter of weeks the knots need to rebuild their fat reserves and double in weight." "To achieve this, each knot must eat as many as 400,000 eggs - a tall order given the skill and effort needed to swallowjust one." "Head down, feeding non-stop means it's hard to be alert to predators." "A peregrine falcon." "With egg laying complete, the horseshoe crabs now leave these shores while the knots gather every last egg they can find." "It's time for the birds to move on." "The knots still have a further 2,000-mile non-stop flight to reach their breeding grounds in Canada." "Flight gives birds many advantages, but there's a period in their lives when they are forced back down to Earth." "The nesting season." "This is the time when they are at most risk, so they must find the safest possible location." "Few go to greater extremes than lesser flamingos." "They nest in the remotest corners of Africa's caustic soda lakes." "Like their reptilian ancestors, birds lay waterproof eggs." "Despite this, flamingos still protect theirs on special mud-stack nests as the lake is prone to flooding." "It's alsojust a little cooler up here." "Temperatures at ground level can reach a blistering 50 degrees Centigrade." "Once a chick hatches, it spends the first six days in the nest." "This is when it's at its most vulnerable - totally reliant on its parents." "The caustic mud deters predators." "But the adult flamingos can cope in this quagmire, because of their long, scaly legs." "Any chick that slips from the nest, however, is treading on very dangerous ground." "This parent encourages her chick to climb back to safety." "Raising chicks requires huge parental investment in both time and labour, wherever you are." "Few places are tougher than the Antarctic." "Chinstrap penguins." "Every day they travel up to 50 miles out at sea, hunting for krill." "But the hard part is getting this food back to the colony, because it sits on the ice-free rim at the top of this giant volcano," "Deception Island." "For the returning fishing party, the first challenge is getting ashore." "The beach is steep, with a powerful undertow." "This female lands safely, but she now begins a longjourney on foot." "For a flightless bird, getting to the top of the volcano means a gruelling climb, especially when glaciers, covered with muddy volcanic ash, stand in your way." "It's like a game of snakes and ladders." "A combination of beak, wing tip and feet." "And she wins through!" "Now she joins penguin rush hour." "Almost home." "She's reached the crater rim, but her trials are still not over." "She must now try and find her family... among more than a 150,000 birds." "Her hearing is so acute she can identify the individual cry of her own chick in the din." "She's made it and the family welcomes her return." "The result of all this parental effort, a mouthful of krill." "Now it's her partner's turn." "A chick's demands are endless." "Sometimes they can push parents to desperate lengths." "But birds are masters of improvisation." "Dassen Island, off the coast of South Africa, is home to a nesting colony of great white pelicans." "There are chicks of all ages all with a hefty appetite." "The parents have a formidable task." "These pelicans are among the heaviest flying birds in the world, weighing up to 10 kilos." "A V-formation is the most energy efficient means of flying." "It significantly reduces drag for the bird behind." "Pelicans normally fish along the coast, but a shortage of food supplies has forced them to look elsewhere." "Cape gannets plunge deep, hunting fish beyond the reach of the pelicans." "But the pelicans aren't after fish." "Their sights are set on a bigger catch." "Malgas Island is the nesting ground for some 60,000 Cape gannets." "Normally one gannet parent goes off fishing while the other looks after the chick." "But declining fish stocks means both parents are often away hunting at the same time, leaving their chicks unguarded," "something which hasn't gone unnoticed by the pelicans." "Only chicks with parents at their side, or those too large to swallow, have a chance." "Back at the pelican colony, the parents regurgitate partially-digested gannet chicks for their brood." "Although most seabird colonies on the African Cape are in decline, the population of white pelicans nesting on Dassen is growing." "When birds come together to breed, and before they commit to one another, they will often perform the most remarkable displays." "One of the most enchanting happens here, on the lakes of Oregon." "Clarke's grebes mate for life, but the female must test her partner's continuing commitment, and she does this by inviting him tojoin her in a ritualised dance." "To strengthen their bond, he offers her a gift." "Now, with eyes only for one another, the faithful pair reach the climax of their dance." "Other birds don't form pairs." "Instead a male tries to mate with as many females as he can." "Male sage grouse gather in the grasslands of Wyoming to advertise their virility with a finery of feathers and proud posturing." "Females are much drabber-looking, but extremely choosy." "They will only mate with the most impressive male, and they judge a male's worthiness by the sounds he makes." "Birds go to great lengths to impress their partners." "In the forests of New Guinea, they famously use colourful feathers and song to maximum effect." "Birds of Paradise." "But in the western part of the island, these flamboyant birds share the forests with a rather unassuming-looking character... the Vogelkop bowerbird." "He might lack the plumage, but he's got an extraordinary repertoire of song." "And, he's a wonderful mimic." "Those are pigeon wing beats." "That's a modest tiger-parrot." "And that, a sulphur-crested cockatoo." "Even more surprising he's an avid collector, with a very appreciative eye for colour." "This male favours red and orange flowers." "And he's very fond of fungus." "Not everything he collects stays where it should." "He puts these treasures on display within and around a construction that has taken him years to build." "A giant bowerwoven around a central sapling, carpeted with moss." "This grand design is no nest... it's the ultimate seduction parlour." "But he's not alone on this hillside." "He's got six rivals within earshot." "This one prefers darker colours, decorating his bowerwith deer dung." "And charcoal." "Visual effect is of crucial importance." "Clearly he hadn't planned on all this sprouting fungus." "He and his nearest rival live a stone's throw apart." "Competition is intense." "It's the dung-ball bower that is the first to catch the female's attention." "He withdraws, while she inspects his workmanship." "She's back again, and seems impressed." "But on closer inspection she is less convinced." "Perhaps itwas that sprouting fungus!" "Back at the flower bower, the male performs a dress rehearsal." "He senses she's watching." "This is the moment he's been working towards." "His bower channels his song in her direction." "A final check." "All is to her liking." "Few birds devote such craft, effort and ingenuity to achieve this life-defining moment." "But here on Kenya's Lake Bogoria, these massive pink slicks signal the start of perhaps the grandest courtship event in nature." "In certain years, when the lake is at its richest, more than a million lesser flamingos congregate to feed." "It's now, when they're in their prime, that they must find their preferred partner." "To do that they perform a remarkable promenade." "With heads held high and neck feathers ruffled, making them look as pink as possible, more and more birdsjoin in the courtship march and pairs begin to bond." "Small groups merge with larger ones until almost 1,000 flamingos are on the move." "From the equator to the poles, birds have found the most ingenious ways of overcoming the many challenges of life, and everything revolves around their unique attribute, feathers."