CCG... when ya catch a bird and separate it, make sure it's out of sight but within earshot of the other birds. If you stand there watching the bird, waiting for it to give up it's gender... it usually won't Buck-wheat. So grab a chair and be sure to sit out of sight of the bird. Ever hear of beer sexing? You can integrate that method with the separation method if you wish. (You can look that up over in the Quail forum section if you don't know what beer sexing is, lol). I wouldn't try beer sexing humans if I were you tho... lol.
Used to have several kegs at the barn all weekend long, and one bucket for everyone's keys. As the nights continued, I was among those very few reasonably sober guys left, whereas most women don't drink all that much beer ... effectively changing the female/male ratio from 2/5 to 8/1 proves that beer sexing humans works shamefully well ~'-)