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.

In 1961, two years before the debut of one of the freakiest films in history, hoards of disoriented seabirds rammed themselves into the sides of homes in the Monterey Bay area. There seemed to be no explanation for the bizarre event, but Hitchcock is said to have based The Birds on it.

More than two decades later, in 1987, four people died and 100 were hospitalized on Canada's Prince Edward Island after eating mussels.

In 1991, there were several animal stranding events in Southern California.

It turned out the events were connected. It all fed into the mystery that captivated Hitchcock and the rest of the nation. Stumped by the strange events that had occurred over a 30-year time period, scientists searched for answers. What could cause such absurd and deadly behavior?

Researchers now know: the answer is in the algae. By examining the contents of the stomachs of animals, they found toxin-making algae that cause amnesia, disorientation and seizures.

Oceanographic researcher Sibel Bargu of Louisiana State University, who worked on this study, has long been fascinated with the story of The Birds. "I have a special connection to this movie," she said. "When I was a kid, they showed it on TV and my parents didn't let me watch it. While they were watching in the family room, I was outside, trying to see the movie from the keyhole. What I saw was so scary."

Bargu went on to become an oceanographer and lover of all things Alfred Hitchcock. "When I started work on harmful algae blooms and their toxins and then learned of this superexciting connection, I felt I had to work on this."

And work they did. Bargu and her colleagues found a connection between the algae consumed by the victims of the events in 1991 and 1987, leading them to believe the algae was also responsible for the original 1961 incident - thus solving the mystery of The Birds.

And while the mystery of The Birds has been solved, the horror and the legacy remains.