At the beginning of "Winged Migration", an onscreen caption declares that no special effects were used to capture the scenes of birds in flight. That might sound like a pretty redundant start to a factual documentary, but given the amazing footage the film delivers, it would be easy to believe that this must be a computer-generated fake.

Taking five crews three years to complete, using a host of innovative filming techniques (from remote controlled gliders to helicopters and balloons), "Winged Migration" is a quite astounding feat of cinema. It does for our feathered friends what Jacques Perrin's previous production, "Microcosmos", did for creepy crawlies.

Covering hundreds of thousands of miles and focusing on hundreds of different species, it celebrates the poetic beauty of flight, shifting restlessly from one location to another to show different birds dealing with different situations.

From the polar ice caps, to the desert, to the countryside of Europe, this is a hypnotic journey that's full of surprises (following a flock of birds as they soar under bridges spanning New York's Hudson River is literally spellbinding).

Emphasising cinematography over natural history, Perrin gives little background to the onscreen action. Occasional captions identify some of the species and there's the odd moment of voiceover narration (in Perrin's thick French-English accent) to bring us back down to earth. But for the most part, this avoids David Attenborough-style educational commentary in favour of visual spectacle.

Ultimately, it's this lack of insight that's the film's one flaw. Watching these birds, you're eager to know more about them and their habits. But then, if "Winged Migration" stirs enough interest in its audience to send a new generation of novice ornithologists to the library, Perrin would doubtless feel his film has served its inspirational purpose.

"Winged Migration" is released in UK cinemas on Friday 5th September 2003.