I have what I think is a bird in the woods near but and I have never ever heard the sound itmales before, its a deep womp noise, I have googled all sorts of garden bird and even a few migratory but still can't find anything at all similar. It's not around often and I have a Really quiet and not amazing clip of it. But not knowing what it is is driving me mad lol
2013 photos & vids here
eff37 on Flickr