Something Wicked in the Woods

Last night I woke to the strangest sound I've heard in a long time. I thought maybe my stomach was growling, but it came from outside. It was like a long drawn-out growl mixed with what sounds like the word "whirl". But a kind of softened-around-the-edges growl. Something from deep in the throat of the baddest-ass bird in the universe. I mean, it's got to be a bird.Anyway, I'm checking my email tonight and the damn thing is out there again making that sound. And I can't find it in the dark. Or it doesn't want to be found.Our backyard is wooded, we're on a corner lot, and it could be hiding anywhere. But I've never ever heard this sound before. Last night I thought it might be a crazed coyote or fox, but tonight I'm sure it's some kind of bird. Very odd. I've never heard a soft growl mixed with the word "whirl" before. Maybe I'm just cracking up...