Will look into Carolina Wren.
Given what I found out about the complexity of "chick-a-dee-dee-dee" being one of the most complex calls in the animal kingdom according to one wed site, I was actually content enough to make the jump and say, "okay, it is a local variation of a chickadee". Have only ever heard it here in SE MA.
Wren theory has promise though, it is warm weather call only, which could be a migratory bird.
Don't think is is a mocking bird, but I am not completely sure of it. (They seem to be more predominant is places I wouldn't be paying attention. Odd how it seems to be picky about altitude and human occupation density.)
Can rule out a cat bird.
Have spent a most of my life, hunting, fly fishing, canoeing and backpacking. This 10 beat cadence is just something I can't identify. Most of what I know about birds are the bug eaters who like to fly over rivers at and after sunset.
Not this: https://www.youtube.com/watch?v=PVgfrTGksxU
Pretty close to this: https://www.youtube.com/watch?v=7GLIFUtXj2M
(9 beats instead of 10 again)