Jason, As Paul Sullivan suggests, your mystery bird was likely a crow or Steller's Jay (Common Raven would be less likely on Mt. Tabor). A few years ago I was in a suburban Eugene neighborhood right in town and I heard persistent toots that sounded like a N. Pygmy-Owl. I finally realized that an American Crow sitting on a nearby light pole that was making the noise. Similarly, just last week I heard a very dull low-volume sound that had a nasal, almost goose-like quality to it. Again, it was a crow that was close by. I actually captured the sound using the video function on my iPhone. Corvids make all sorts of odd noises that are often quite unlike their typical vocalizations. Dave IronsPortland, OR > Let me suggest your mystery bird is a Corvid: Raven, Crow, or Steller's Jay. > They can make hollow sounds, often in a toot-toot rhythm. At this time of > year the Stellers are secretive; they're nesting and slinking around giving > quiet sounds that we don't hear the rest of the year. > > Good birding, > > Paul Sullivan