What bird makes this deep gutteral clucking/clicking/knocking sound and no, it is not a woodpecker

by tpindar
(Savannah, Ga. )

I live in southeast Georgia. I repeatedly hear a bird that makes a deep clicking/clucking sound that is very steady and true - a distinct pattern. Not real fast but not slow either. I thought I saw a bird high in a pine tree that was making this sound and it looked like it was a relatively large black bird. Trying to identify it by its color, I have listened to recordings of ravens, crows, blackbirds, grackles and none of the recordings sound like this bird. I have only had this one glimpse but hear the bird regularly. Can anyone help? So unique a sound.