"Winged Migration" looks at birds intimately, in shots that seem impossible. The movie offers only a few well-known facts about bird migration: Birds fly hundreds of miles south in winter (or north, if they live in the Southern Hemisphere), and navigate by stars, by the sun, by Earth's gravitational field and/or by familiar landmarks. But the film's purpose is that we simply look at birds closely. Showing memorable footage, with long, aerial tracking shots of birds in long-distance flight, into the wind, it lets the viewer realize how hard birds work to fly so far. When they stop to eat - one easily slides a whole fish down its long throat - to feed their young, then courting in chest-thumping rituals, we see how serious their business is. Other birds are trapped in industrial waste, and in a more-horrible scene, a bird with a broken wing can't escape a beach full of crabs that catch it and pile onto its still-living body. In nature, life is all about getting enough to eat.

Variety's correspondent Lisa Nesselson tells how the footage was achieved: 225 feet of film were shot for each foot in the movie, and some birds were bred to be in the film - exposed to airplane and movie camera sounds while still in the shell, and greeted upon their birth by film crew members. (Newborn birds instinctively assume that whomever they see upon emerging is a parent.) Some footage was shot from ultra-light aircraft, some from hot-air balloons, and other shots seem almost scripted: Birds move toward the camera as it pulls back. Scenes manufactured in the editing room include one in which the viewer sees snow birds in alarm, then hears an avalanche, then sees a quick cut to long shots of the avalanche, matching shots of the birds in flight, although the camera couldn't have been in the avalanche's path.

The film's slant toward the visual and away from narration or facts droned into one's ear, whether encyclopedic or sentimental comments, would limit the film's visceral impact. Life is hard, and birds work hard at it. A shocking sequence of ducks in magnificent flight against the sky shows them dropping, one by one, as hunters gun them down, and it reminds us that birds have flown, exhausted, for days before meeting such an end. We don't so much blame the hunters as wish the ducks could shoot back.