Billy is a 14-year-old schoolboy approaching the age where he is expected to leave school and work in the local coal mines. Physically diminutive and socially isolated, he resists a strict, apathetic school system and a neglectful home environment. Despite these hardships, he possesses an intuitive understanding of nature and wildlife, finding peace in the countryside. His connection to animals offers him a rare opportunity to express care and dedication.

Jud is Billy's older half-brother, a young man who works long, grueling hours in the local coal pit. Stifled by his socioeconomic reality, he embraces an aggressive stoicism and relies on heavy drinking and gambling for distraction. He embodies the exact future that Billy desperately wishes to avoid.

Mother is a working-class woman raising Billy and Jud in a highly judgmental, patriarchal mining town. She struggles with the crushing realities of poverty and seeks brief distractions through romantic relationships, drawing the gossip of her neighbors. She is highly resistant to emotional vulnerability and leaves her sons to fend for themselves emotionally.

Mr. Farthing is an empathetic English teacher who stands apart from the rest of the school's faculty. He actively works to involve his students in lessons rather than simply demanding their obedience. He is the first adult to recognize Billy's intelligence and specific talents, offering him a glimpse of positive mentorship.

Kes is a young kestrel that Billy takes from a wild nest and patiently trains. Housed in a refitted garden shed, she is a wild bird of prey that learns to fly to Billy's lure. She represents freedom, the natural world, and a life outside the dark confines of the coal mines.

Principal Gryce is the authoritarian head of Billy's school. He views the working-class boys under his care with open contempt, seeing them as useless members of a failed generation. He relies heavily on corporal punishment, preferring to beat students with a cane rather than understand their struggles.

Mr. Sugden is a physical education teacher who uses sports to assert his dominance over children. He dresses in pristine Manchester United gear and treats casual school games with ruthless, inappropriate competitiveness. He actively bullies weaker students to mask his own insecurities.

MacDowall is a student at Billy's school and a former friend. Larger and stronger than Billy, he uses physical intimidation and cruel gossip about Billy's family to establish dominance. He resents Billy for withdrawing from their social group.

Billy and Jud's absent father permanently left the family years prior after discovering his wife's infidelity. His departure left the household without a paternal figure, heavily impacting his sons' emotional development and financial stability.

Mr. Porter is the local newsagent who employs Billy as a paperboy. He holds deep classist prejudices, openly disparaging Billy's background and assuming the worst of his character.

Mr. Crossley is a teacher at Billy's school who handles administrative tasks. He is largely disengaged from his students, operating on autopilot to the point that he fails to notice when a student is mocking the attendance process until it is too late.

An unnamed farmer who owns the land where the kestrels nest. Initially protective of his property and ready to chase Billy away, his demeanor softens when he witnesses Billy's genuine fascination with the wild birds.

Tibbert is a schoolboy in Billy's physical education class. He is assigned to be a team captain opposite the overly competitive Mr. Sugden during an exhausting schoolyard match.

A local butcher in the mining town. Unlike many adults in Billy's life who view him with suspicion, the butcher is aware of Billy's passion for falconry and kindly gives him meat scraps for his bird at no cost.

Reg is an acquaintance of Mother's, seen quietly exiting the family home. His presence causes friction between Billy and his mother when Billy asks about him.

A man known to Billy as Uncle Mick. His intimate involvement with Mother directly led to the permanent fracture of Billy's parents' marriage.