A bit of Googling has netted some interesting resources which have provided a bit of information, and encourage me to investigate even further!
The first site
http://www.desertusa.com/mag99/oct/papr/raven.html at first made me certain that the bird in question is indeed a raven.
Then I googled a bit further and came upon a second site
http://www.crows.net/calls.html which turns me again to the crow.
However, in my searching I have noted that oftentimes the crow and raven are lumped into one grouping, and thus the second page could very possibly be referring to both crows and ravens.
Meanwhile, now that the violent thunderstorm has passed, the entire yard is now full of cawwing crows which are kicking up one heck of a racket ... but none of them are screaming. Go figure.
If nothing else, I'm learning a lot more about some of the feathered residents of my yard which I had previously ignored in favor of their more colorful neighbors.
