The second programme deals with the mechanics of flight. Getting into the air is by far the most exhausting of a bird's activities, and Attenborough observes shearwaters in Japan that have taken to climbing trees to give them a good jumping-off point.

A look at the constant need to feed necessitated by the demands of flight in species from sap suckers and crows, to robins and geese.

This epsiode looks at those birds that have become strictlt meat eaters from eagles and hawks to owls and vultures.