Nice shot! How close were you? What focal length? Red-Winged Blackbird mothers can be fierce. I saw one at the edge of Turtle Pond in Central Park repeatedly dive-bombing a Great White Egret that had been fishing near the RWB's nest. The RWB was screaming its distress call and coming at the egret feet first. The egret seemed to be about 400 times bigger than the RWB.
I should have gone back and edited that, eh? I literally scared them off the ground next to my feet, then this one flew to a bush about 25 feet away. I was using the Pana G1 at max. zoom, effectively 400 mm. A ranger in that very park asked me whether the parent attacked, and I said no, it just stayed on a bush farther away, about 60 feet distant. I don't know for sure, but I would guess that since I've been photographing those Red-wings twice a week for several weeks now, perhaps the parent didn't see me as a threat. I had those experiences in Bolsa Chica on the West coast, since in a few cases I was able to get within 8 feet of perching hummingbirds, and 15 feet of a perching kestrel.