This film tells the story of maverick scientist John Ostrom and his theory that birds are really just dinosaurs with feathers. Thirty years on and a revolution in palaeontology has proved him right. Horizon looks at the compelling and recent evidence that shows how modern birds fine-tuned their unique design for flight. It also confirms that Velociraptor is more closely related to the sparrow sitting on your bird table than it is to the crocodile.
When archaeopteryx was first discovered in 1861 the world was rocked. Half reptile and half bird, it seemed so fantastic that everyone thought the feathers must have been fake. But, in 1973 a scientist from Yale came up with a controversial theory. John Ostrom argued that birds were not so much related to dinosaurs - they were dinosaurs. He compared the anatomy of archaeopteryx with a new type of raptor dinosaur that he discovered. However, he still had no direct evidence from the animals in-between, the crucial missing link.
At the time he was widely criticised but over the intervening period more and more evidence has vindicated his original idea. Over the last two years, the all important missing links have been discovered in China. Called Caudipteryx it shows the type of animal that lies halfway between the small predatory dinosaurs and Archaeopteryx.
In August, an advocate of the Ostrom school of thought, Mark Norell, flew out to the Beijing Museum of Geology to take a closer look at these remarkable animals and Horizon travelled with him. By analysing the fossils more closely Norell can look at the skeleton architecture that is distinctly dinosaur but also bird-like. Whether Caudipteryx has flight feathers or not is still contentious and part of Norell's mission to Beijing was to unravel this puzzle.
Closely linked with the evolution of feathers was the development of flapping forelimbs - wings! Scientists have taken remarkable x-ray films to study birds flying in a wind tunnel. This allows them to understand how birds flap their wings, using the distinctive wrist bone that they inherited from dinosaurs.
But the fact that birds are descended from dinosaurs doesn't just lead to a shift in classification - it also raises the fascinating possibility of genetically engineering a dinosaur back. Forget Jurassic Park and extracting dinosaur blood from a mosquito. One scientist argues that the best way of recreating a dinosaur is to switch off the genes in a bird that make it bird-like. Get rid of the feathers gene, the beak gene and other genes and, voilà, you have a raptor dinosaur!
State-of-the-art computer animation brings these dinosaurs and ancient birds back to life. This film will ensure that you will never be able to look at the birds in your garden in the same way again.