An enthusiastic young British bird (voice by Ewan McGregor) enlists as a homing pigeon to do his bit for the 1940s war effort. This lightweight animated feature offers a peculiar perspective on World War II: It seems to have been fought almost entirely by birds—pigeons, doves and seagulls against Teutonic falcons. There are ships, planes and highway vehicles, but there’s hardly a human being in sight (a work-saving move, no doubt, for first-time director Gary Chapman). Three writers (George Webster, Jordan Katz and George Melrod) are too many cooks for the script’s thin stew of heroic clichés and hoary gags. Still, the deft crew of animators and stellar voice cast (including Hugh Laurie, Jim Broadbent, Tim Curry, John Cleese, John Hurt and Olivia Williams) make the movie a pleasantly amusing diversion.