Hitchcock’s ‘The Birds’: Mystery Solved

[Donna]

The Birds, the jaw-dropping thriller that has spooked the nation since 1963, was inspired by a real — and equally eerie — event.  The mystery that prompted Alfred Hitchcock to make the film has been solved: The birds had ingested a toxin that caused them to act strangely.

http://abcnews.go.com/blogs/entertainment/2011/12/hitchcocks-the-birds-mystery-solved/