The film, directed by John Frankenheimer in 1962, stars Burt Lancaster as Robert Stroud, a murderer who is sent to a maximum-security prison in Leavenworth. Stroud is a man full of anger and antisocial behavior, although the head of the prison (Karl Malden) thinks that there is some good in him... it'll just take time for him to be rehabilitated. Malden's attitude swiftly changes when Stroud ruthlessly murders a prison guard, mainly just for being a real stickler to the rules, although Stroud believes that is just an excuse to treat him unfairly.
After three trials, Stroud is sentenced to hang, but the tireless efforts of his mother (Thelma Ritter) allow him to escape the noose. However, this doesn't stop Malden from at least being able to severely punish him -- originally, Stroud was sentenced to remain in solitary confinement until his day of death, so Malden says, well, that's the way it will remain, even if Stroud's day to go isn't until nature, rather than the hangman, deems it so.
Time passes. One day, while outside during a rainstorm, Stroud sees a wounded baby sparrow. Something inside him makes him take the sparrow back inside, and nurse it back to health. Along the way, he ends up having to teach the bird to fly, and to train him in other aspects as well. He manages to impress a number of people, including one of the prison guards, and some of the other prisoners, with his efforts.
Later on, he manages to get, not just birdseed, but even other birds in his cell, as he becomes fascinated with learning about these creatures. He also reads books about bird illnesses and the like, and writes on his own experiences, sending them to magazines. He wins a prize in one of the more respected publications on birds. He gets into business with a woman, in which he produces a medication that he had inadvertently created while trying to find something to cure a serious illness among all the birds that he kept. He then writes an entire book that was considered groundbreaking in its time. Near the end of the movie, he is said, by an animal doctor who visited Stroud occasionally when he needed assistance, to be one of the most knowledgeable experts on birds hat he has ever witnessed. Stroud accomplishes all of this while in solitary confinement, never once leaving the building, and only very occasionally being able to leave his actual cell to see visitors.
