And I don't think I've ever seen a bird that combined more 2nd best attributes of more birds. It generally has the shape of a Red-winged Blackbird, but not the epaulets. It has the glossy plumage of a Brewer's Blackbird but not the bright eye.
It has the broad head of a cowbird but neither a brown hood nor a red eye.
You'll notice it has a lot of worn feathers in the wings and faded brown primaries. My assumption is that this is a first year male; females and young Shiny Cowbirds are brown.