Report 2760: Environmental Engineer hears calling and responding screams

On Monday night (actually early Tues. morning July 3, 2001) I was performing some nighttime noise monitoring at a residence outside of Shelton, Washington.  I monitored from 2:30 am to 4:30 am.  There are a few residences where I was, but the area is surrounded by Simpson timber land.  The Washington State Penitentary is closeby.  It was perfect noise monitoring conditions, clear night with no winds at all (extremely quiet).  Right when I started my measurement I heard coyotes from the direction of the driveway, off in the distance.  A few dogs in the distance barked at the howls.  I then heard some different animals.  I heard 2 or 3 screams from one location and a single scream in response from further north.  These screams seemed to be communicating to each other.  It lasted about 30 seconds or so.  The dogs in the distance continued to bark, although the 2 dogs in the yard with me did not. I was really wondering what animal it could have been.  I would describe coyote howls as an owwwoooooooo noise.  These screams started as a howl but ended in a scream, like ooooaaaahhhcchhh.   The ending part sounded like a woman screaming, but the scream was solid-sounding and not screechy.  It sounded about a half-mile away but still very loud and clear. Now maybe you can tell me...  It could have been mountain lions, but I am not sure if those animals are 'group' animals.  Maybe it was a mother and her cubs trying to find each other.  It just did not sound cat-like to me, although I have not heard mountain lion calls specifically.