It looked like a scene out of Alfred Hitchcock's "The Birds" as thousands of blackbirds and starling roost near a Modesto Shopping Center.

The site was a bit freaky, but that's exactly what the birds are trying to do.

"Basically they come to roost like this because there is protection in numbers," said Don Schmoldt with the National Audubon Society. The birds also look for trees that maintain their leaves yearlong for additional protection.

This is not the first sighting of this size in Northern California. In February, Target in Sacramento saw a similar roost of Black Headed Cowbirds. But why the attraction to big box stores?

"I think that gives added protection the birds can see predators," said Schmoldt.