In the video, shared on Twitter on Saturday, a scared-looking woman can be seen running to the entrance of the supermarket while frantically waving her arms as if petrified that one of the animals will brush against her.
The army of birds – believed to be great-tailed grackles – can be heard calling to one another in high-pitched whistles and tweets as they rest on the ground.
According to local news sites, the spectacle happens every year when the birds migrate but some people insisted it was a “bad omen”.
“The end times,” tweeted one viewer solemnly.
A second person said: “Isn’t it some kind of omen?
“Deal of the century followed by devil birds?”
However, other people poured cold water on the idea of the birds being a herald of doom.
Flippantly, one person asked: “Is ‘devil bird’ a new species? Never heard of it.”
“Why are they called devil birds?” asked another.
In Hitchcock’s 1963 film The Birds, humans are attacked and killed by swarms of birds that start randomly attacking a town.
Great-tailed grackles are native to North and South America and can reach a flock size of up to half a million members, according to allaboutbirds.org.
This comes after people were horrified when hundreds of birds dropped dead on a quiet road in Wales.
Birds were also seen “falling out of the sky” in Coventry, sparking conspiracy theories.