Wrote Roger Ebert on January 16, 1973: "Kes" was directed by Ken Loach, a young British filmmaker who has now made three movies of high quality and disappointing commercial performance. His "Poor Cow," with Carol White, was an ambitious but somewhat confusing movie about a barmaid who becomes pregnant; it would have fared better, I think, in these latter days of women's lib. After "Kes," he made "Family Life," which got good notices at the 1972 Cannes festival and opened in New York last fall as "Wednesdays Child." This was the story of a misfit adolescent girl and her uptight parents, and it was effective in a grim, slice-of-life way.
But "Kes" is Loach at his best. He shot it on a very low budget, on location, using most local nonprofessionals as his leads. His story is about a boy who's caught in England's class-biased educational system. He reaches school-leaving age and decides to leave, but doesn't have anything else he much cares about. He's the butt of jokes and hostility at home (where his older brother rules), and inarticulate with his contemporaries.
One day he finds a small kestrel hawk, and trains it to hunt. The bird becomes his avenue to a free and natural state - the state his soul needs, and that his home and school deny him. And then the system, alarmed or offended by his freedom, counterattacks. The film has a heartbreaking humanity.