I photographed this guy last week in Wakodahatchee here in south Florida and am in doubt as to its ID.
From its physical size and shape, I think it is a young Boat-tailed Grackle. Am I correct?
I think the problem you are having is in that this bird is exhibiting leucism.(http://en.wikipedia.org/wiki/Leucism) Try picturing the bird without the white feathers. I am not familiar with grackles so unfortunately I cannot ID this birds.
Looks good for Boat-tailed with abnormal feathers. I've seen this in Boat-taileds in NJ occasionally. Some of the feathers look a bit old and the gape has no pale area, so I suspect that this is an adult female rather than a juvenile.