Sounds like possible algal poisoning, so called "red tide"?
from-
www.sfgate.com/bayarea/article/Search-is-on-for-killer-plankton-Puzzling-sea-2840364.phpThere have been outbreaks of toxic algae many times in the past, scientists now believe. Some suspect that the phenomenon can be traced all the way back to biblical times. In 1998, the deaths of more than 400 sea lions in one month off Central California were attributed to this particular diatom phytoplankton.
"We now suspect that domoic acid poisoning was also the cause of a massive bird poisoning in 1961, which resulted in birds acting as if they were intoxicated," Cochlan said.
That event is believed by some scientists to have been part of the inspiration behind the fictional marauding birds of Alfred Hitchcock's 1961 classic, "The Birds."
