I really like the perch in this image - it creates an unusual and engaging posture for the bird. Good exposure on this difficult subject. I find it is far too easy to underexpose the black feathers on the red winged blackbird.
The background is okay - not too distracting, but a little patchy. Finally, the underside of the bird (at least on my monitor) is all black w/ no shadow detail. I'm fine with it - I always prefer a photo with more contrast and some shadow detail missing, than low contrast with full shadow. But perhaps this shot could have done with some dialed down fill flash to light the bird's underside just a little bit.
Rick, the eye, beak and head are sharp with good detail. From my limited experience and from looking at other posted images, these birds are hard to get the all the blacks with detail. I really like the perch, foot position, and the composition.
I am assuming that if using flash, one would need a way to project it (better beamer?).