In reply to Tero's post (#3): I'm really not shore... most of the time, I see one of them (either male or female), and after a few minutes, the opposite sex drops by, and they dine together, and often fly away before I get to my camera. This also applies to the Common Grackles we get (One of them had lost an eye).
However, I'm a little unsure of where I stand regarding the Brown-Headed Cowbirds. In case you don't know, cowbirds have a fetish for laying their eggs in another bird's nest. This has gotten the attention of various conservation groups, and in some places, especially where endangered and/or rare species of birds nest, you can shoot and kill the cowbirds to keep the rare species safe from the cowbirdlets. I've heard that when the cowbirdlets hatch in the host's nest, the cowbirdlets typically are more bossy (wants more food, etc.) and thus the host's babies usually starve to death. Some other species of parasitic birds have babies that actually push the host's eggs out of the nest and *splat!* the eggs go when they hit the hard ground...
But really, don't shoot them at all, we're all conservationists here. Passenger Pigeons were plentiful, and some states voted to not pass bills protecting them, and people shot and killed them into extinction.....
EDIT: Internet connection was disrupted at 12:30AM eastern time while typing.