The North American cognate to Oz's corellas are grackles, and usually in the mix are a lot of smaller starlings. From a few years ago, a grocery store parking lot in Houston. Since I don't commute to work now I don't see them so often, there were places at a few parking lots and highway intersections where they would be perched on all of the overhead phone and power lines and in all of the trees and on the grassy areas.