Two friends arrive back from Vietnam, scarred in different ways. One has physical injuries, the other has mental problems that make him yearn to be a bird, a subject he has always been fascinated with.
THE most unusual thing about ''Birdy,'' Willam Wharton's novel about a boy who develops an overwhelming erotic fascination with avian life, is its lack of allegorical implications. The story of Birdy, who actually reaches the point of imagining that he has fathered a family of canaries, can be taken at face value. So can the parallel tale of Al, the boyhood friend who years later, after suffering grave wartime injuries, returns to coax the adult Birdy out of his madness.
Like Mr. Wharton's novel, Alan Parker's film of ''Birdy,'' which opens today at the Beekman Theater, works best when it concentrates on the friendship, and on Birdy's amazing eccentricities. The material is so odd and so powerful that its particulars are of much greater interest than its larger implications. It is some measure of just how compellingly Mr. Parker has set forth this tale that when, barely 20 minutes into the movie, Birdy and Al don feathered pigeon suits for a nocturnal adventure, the episode seems neither silly nor incredible. Birdy's intensity is so captivating, and Al's discomfiture so believable and funny, that their story becomes irresistibly involving.
The film takes the form of a series of flashbacks. Its present-day sections are set in a military hospital, where Al (Nicolas Cage) tries desperately to elicit some human response from his friend. Birdy (Matthew Modine) has finally transformed himself into one of the creatures of his dreams. He stares at Al with one eye, birdlike, and perches naked and motionless on the railing of his hospital bed. These scenes are contrasted with glimpses of the younger, happy-go- lucky Al, whose interests are girls and weight lifting, and the delicate, grinning Birdy, whose obsession has not yet drawn him away from human contact. Mr. Modine's performance is exceptionally sweet and graceful; Mr. Cage very sympathetically captures Al's urgency and frustration. Together, these actors work miracles with what might have been unplayable.
Mr. Parker has for the most part directed the film deftly and unobtrusively. Every so often, though, he introduces the kind of overstatement ''Birdy'' didn't need, as in a shot of Birdy lying Christlike on the floor of his hospital room. The disco music accompanying Birdy's first dream of flight, the adolescent sex scenes played bluntly for laughs and the combative ending seem similarly unnecessary, as does the updating of the story from the World War II of the novel to the Vietnam era. Fortunately, the heavy-handedness is in limited supply. Most of ''Birdy'' is enchanting.
The film contains many brief but memorable vignettes, particularly those involving the boys' families; Sandy Baron is especially good as Al's blowhard father, and George Buck has a touching scene as Birdy's father, who works as a janitor at a school and is there cleaning bathrooms on the night his son attends a prom. In addition to its human players, ''Birdy'' has a large animal contingent, with some remarkable footage of canaries being hatched. To the extent that any film could translate Birdy's obsession into visual terms, this one has. Mr. Parker, in filling the film with animals and studying their motion without giving any of the canaries speaking lines (the book's Birdy has a winged ''wife'' who eventually begins talking to him), has been wise to leave well enough alone.
Airborne Dreams BIRDY, directed by Alan Parker; screenplay by Sandy Kroopf and Jack Behr, based on the novel ''Birdy'' by William Wharton; director of photography, Michael Seresin; edited by Gerry Hambling; music by Peter Gabriel; produced by Alan Marshall; released by Tri-Star Pictures. At Cinema 1, Third Avenue and 60th Street. Running time: 120 minutes. This film is rated R. BirdyMatthew Modine Al ColumbatoNicolas Cage Doctor WeissJohn Harkins Mr. ColumbatoSandy Baron Hannah RourkeKaren Young RenaldiBruno Kirby Mrs. PrevostNancy Fish Birdy's FatherGeorge Buck Birdy's MotherDolores Sage Joe SagessaRobert L. Ryan Mario ColumbatoJames Santini
