Thanks to everyone who gave me ideas on the identity of the dusk screecher
on P5.. and my yard. I haven't heard it again, but I've been listening to
audio-file after audio-file and still nothing matches it.

  The only ones who come close to matching the frequency/pitch and sound
clarity would be a loud Screech-Owl whinny IF it had NO tremulousness at
all, and rose then fell in a second or two, and then be silent.  The
Sasquatch site has 2 recordings of what they identify as N. Saw-Whet owl,
and those recordings have a very similar pitch and clarity, (not sure those
are correct sound terms) but that's the only site I've ever found of a
Saw-Whet owl making any noise but tooting or some kind of squeaky noise. I
just read that Saw-Whet Owls like to nest in hollowed out pileated
woodpecker holes, and there sure are a lot of those out on P5, but I guess
it is too early for them to be thinking about nesting.. but maybe
establishing territories?

I've listened to a lot of Barred Owl recordings (everything on the Macaulay
library site)  but most, if not all of them I could recognize or could
easily imagine coming out of a Barred Owl's beak. There really was no
hoot-like, toot-like, raspy or tremulous quality to the sound. I think it
was a noise a(n evil) person COULD have easily have made.

 I've got to get used to carrying my iphone with me during the evening with
my finger poised on the RECORD button! I'm not sure if it ever repeats the
noise, though, so I have to be vigilant and have quick reflexes! (Something
tells me I'm not going to get a recording : (     )

Maybe someone else in the Norwich area will hear it and be better at
describing it than I am. I will try to get up the nerve to go out there
again around the same time of afternoon. Has anyone ever heard a dear
actually scream? Not snort, but scream like a woman? I've never heard it
but there are people who insist that they have heard it.