So this is a real thing: a “big year” is an adventure and a competition among North American birdwatchers to see who can spot the most different individual species of avian in a single January-to-December span. This actually happens, and The Big Year is based on a nonfiction book by journalist Mark Obmascik [Amazon U.S.] [Amazon Canada] [Amazon U.K.] about one actual year during which three very different guys vied for the title of America’s biggest bird nerd. It’s sorta one of those “you can’t make this up” things, and yet screenwriter Howard Franklin (Antitrust) and director David Frankel (Marley & Me) have turned it into a charming little narrative movie that is so amiably ridiculous that you’re sure it must have been invented. Here we meet Brad Harris (Jack Black: Kung Fu Panda 2), a divorced computer programmer; Stu Preissler (Steve Martin: It’s Complicated), an about-to-retire corporate executive with a supportive wife (JoBeth Williams: In the Land of Women); and Kenny Bostick (Owen Wilson: Cars 2), a building contractor married to a woman (Rosamund Pike: Johnny English Reborn) who’s fed up with his hobby — all with different motives for doing their own big years, all of whom will learn something about themselves along the way. Because of course, while this may be “the birdwatching comedy” that Hollywood was so terrified of trying to market that it was all but ignored, the birdwatching angle completely hidden, this pleasantly sentimental flick is really about life, the universe, and everything. The birdwatching is only, you know, a metaphor. It’s the peoplewatching that is amusing here: observe the fascinating behavior among the birders who work on an honor system when it comes to counting their sightings but don’t hesitate to cheat and distract up to that point. The three stars bring their most satisfying games, their comedy small and human-scaled rather than broad and slapsticky: Black is so much more appealing as the sweet man he plays here rather than the overgrown child he’s often cast as; Martin is smooth and confident as a man who knows what he wants out of life; and Wilson is nice as a comic foil who doesn’t quite realize he’s the villain of his own life. There’s nothing extraordinarily surprising here, but it’s a rare grownup comedy that diverts without being crude and disgusting.