Aint Googling wonderful! Look what I found,

The name ‘Winnie-the Pooh’ was the co-creation of Christopher Robin Milne (AA Milne’s son) and a Canadian army lieutenant, Harry Colebourn. En route to the trenches during the First World War, Colebourn acquired a female black bear cub from a hunter, and named it Winnipeg, or Winnie for short. He left the bear for safety at London Zoo before going on to fight in France. Christopher Robin, visiting the zoo, became very fond of Winnie, and began calling his favourite teddy-bear ‘Winnie-the-Pooh’ – ‘Pooh’ was the name he had given to a swan he had met while on holiday at Angmering in Sussex. AA Milne began to keep a journal of Winnie-the-Pooh’s adventures, which later did rather well at the bookshops. The real Winnie continued as a star attraction at the zoo and died in 1934.