Very cool visitors. I think the ones I have up in the trees may be Ravens, but I haven't really got a close enough look at them. There seems to be only a few which is why I tend towards ravens vs. crows. One of them has a very strange Croaking/Grunting sound vs. a standard Caw. Ever heard of that? I mean like at first I thought it was like a huge Deer grunting out there or something, but it's definitely from the raven/crow. I'll try to catch some sound bytes this weekend and still aiming for the drone zoom shots.
Ravens do have deep voices, and make calls like quork and gwah and croak. Ravens are also much larger than crows, and have a wedge-shaped tail and a beard. Since you seem to live in a woodsy area, I'm guessing ravens. If you have a photo I can look at it and tell you!