Okay, I know they do because I have seen my African Grey parrots blink. Also, Wesley won a staredown contest with Ozzie Bird the other day. But do they blink like humans blink?
I found the answer, on Yahoo Answers: They most certainly do blink. Birds have three eyelids - an upper and lower lid, like we humans have, and a third called the nictitating membrane, which moves horizontally across their eye, and serves the function of lubricating and cleaning the eyeball. Most birds and reptiles have these, as well as some mammals.
The source of this was http://www.earthlife.net/birds/vision.html