The story of a historian's experience training a hawk while recovering from her father's death has become the first memoir to win Britain's prestigious Samuel Johnson Prize.
"H is for Hawk" by Cambridge university historian Helen Macdonald, 43, was the favourite to win the £20,000 ($32,000, 25,500 euros) prize for non-fiction.
The first memoir to win the prize in its 15-year history, the book is an account of Macdonald's grief over her father's unexpected death and decision to train a young goshawk, Mabel, a pursuit that came to dominate her life.
Macdonald "has written a book unlike any other, about an obsession with a wild creature, brought to life in prose sometimes technical and always striking," said chair of the judging panel Claire Tomalin.
"Writing about wildlife and the environment has never been better or better informed than this."
The book is interwoven with a biography of troubled novelist T. H. White, author of the Arthurian series "The Once and Future King", who wrote his own account decades earlier about his struggle to train a hawk.
"She is a conjuring trick. A reptile. A fallen angel. A griffon from the pages of an illuminated bestiary. Something bright and distant, like gold falling through water," Macdonald wrote of her first glimpse of the hawk Mabel when she bought her from a breeder.
"In a way, Mabel kept me in the world, but it was a very strange world. I was becoming less and less human because I spent so much time with her," the author told Cambridge News.
The prize is open to non-fiction categories such as autobiography, current affairs, history, politics, science, sport, and travel.
It was last year won by Lucy Hughes-Hallett for her biography of the Italian poet turned fascist politician Gabriele D'Annunzio.
Also shortlisted for this year's prize were a biography of British politician Roy Jenkins by John Campbell; "The Iceberg", a memoir by artist Marion Coutts; slavery history "The Empire of Necessity" by Greg Grandin; Alison Light's family history "Common People"; and "Village Of Secrets: Defying The Nazis In Vichy France" by Caroline Moorehead.