Probably a great horned owl. The barn owl is only slightly smaller. In the deep south east of the Mississippi probably our most commonly heard one is the barred owl, also known as an eight-hooter owl. It is smaller, about the size of a barn owl, and looks sort of like a barn owl wearing a ghillie suit. I've only seen one in the wild, in fact just this week and it blended right in to the trees at dusk. But you can tell it because it hoots eight times, no kidding. Horned owl sounds more like the classic "Who? Who? Who, who?" Horned owl is seen much more often. I guess when you're big enough to fly off with a half grown guinea you don't have to hide in the woods.
Back about populations I think it is really funny that after all the stir the tree huggers made for so many years about the spotted owl, the spotted owls are being destroyed, not by loggers but by barred owls. Idiots chaining themselves to trees and other nonsense, then as soon as their backs are turned the barred owls come in and take over! HAR!
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In a few years when the dust finally clears and people start counting their change there is a pretty good chance that President Obama may become known as The Great
Absquatulator. You heard it first here on TFL.