Erle Stanley Gardner 
The Case of the Perjured Parrot [EPUB ebook] 

One of Perry Mason’s trademarks is his ability, in court, to switch the physical evidence in a case. He generally does this with guns or bullets, and it confuses the jury, to his client’s advantage. In this case, Perry offers a coroner’s inquest two parrots, one of which swore like a muleskinner and was found near the body of a millionaire hermit who had been murdered.