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Good stitching job, Morris, and an interesting sequence.
I don't know about east coast birds, but from my experiences in Oregon- the red-winged blackbirds chase each other around (enthusiastically) in a non-contact manner while establishing their nesting territories. After the boundaries have been set and nesting has begun, they (usually males, but not always) seriously attack and chase away only predator birds such as GBH, egrets, crows and bald eagles. And they only do it when nesting or while their young are still learning the "ropes." After their young have become competent, the red-wings never bother anybody.
I've spent hours watching these particular behaviors at Baskett Slough National Wildlife Refuge in central Willamette Valley.
Others may have observed entirely different behaviors, I suppose.