Overview: The birds are here. Birds in books. Birds on calendars. Birds on table mats. Suddenly everyone is mad about birds. In some of the most remarkable sequences ever filmed, 'Survival' analyses this universal appeal. Take a night flight with a wild duck. Soar with a vulture as it rides the air currents above high cliffs. Watch gannets, eagles, kingfishers dive on their prey. Admire the frenzied courage of all manner of birds struggling to rear their young. Aubrey Buxton explains why birds are booming as never before