Released 45 years ago (!), compressed into less than two minutes.
...the behavior of the birds in the film may have been based on a real incident caused by poisoning with domoic acid. This chemical is produced when plankton are exposed to urea, a chemical which can leak out of septic tanks and is naturally present in human urine. Contamination can pass up the food chain, resulting in neurotoxic effects to predatory animals.Via Neatorama's Upcoming Queue.
On 18 August 1961, residents in the town of Capitola, California, awoke to find sooty shearwaters slamming into their rooftops, and their streets covered with dead birds. News reports suggested domoic acid poisoning (amnesic shellfish poisoning) as the cause. According to a local newspaper, the Santa Cruz Sentinel, Alfred Hitchcock requested news copy in 1961 to use as "research material for his latest thriller".