They make the weirdest "clacky" noise when they're warning someone away. But they let people get pretty close. I didn't want to scare them too much, so stayed away.
There's another smaller bird that hangs around a lot, maybe a sand piper? They make a cheapy noise. There's a black bird that hangs around the WalMart parking lot. Don't know what he is either. I need a guide book I guess.