Even the end papers and the title page bring the reader into the genre of the classic detective story.  The story is about an out-of-work Pigeon P.I. who is brought back to service when several birds turn up missing.  The clues lead him to his former partner who was tired of being a plain gray pigeon and kidnapped a multitude of colorful birds to provide feathers to add to his own plumage.  Both the illustrations and the tone of the story telling evokes a Dick Tracy type gumshoe story.