I have used one to locate Mountain quail in the past. I would give a go in areas I have found them before and they would answer sporadically. its more of an alarm call to make them give up their location, rather than calling them in.
on a couple different occasions I spotted a covey dusting on an old two track or out in the open, I did my best impression and the birds didn't even bat an eyelash. made me wonder how many coveys I had passed by because I hadn't got an answer.