Well, I'm no expert, as I am still fairly new to button quail. Yet, as GrandmaBird wrote, I also think he may be protesting lack of heat. I don't know where you live, but from what I have learned about buttons, there seems to be a universal agreement among button owners that they are to be kept indoors at night like other tropical birds. When they are warm, they will snuggle down and rest. When they are chilled or distressed in some way, they can let you know by crowing like this. If you do intend to keep them outdoors, keep in mind that these are tropical birds that require the temps that GrandmaBird stated, as well as brush or thicket of some sort to hide under. Do they have grass, pine shavings, or some other soft substrate for them to nestle down into at night? Is there a way for you to provide them with a source of heat at night (you could try a black heat light, as the red might be too bright)? If you already have these things available to them, did you just recently place them outdoors (could still be adjusting to a new environment)? My adult male crowed like this for the first 4-5 nights when I brought the pair home and placed them in a new environment. With everything else in check, he settled down once he acclimated to the new digs. A final thought would be for you to sit out there for a while with them at night. Is the crow hearing other night birds (owls, mockingbirds, nightingales, even crickets, etc...) singing or chirping? With my male button, he will often crow whenever he hears the wild doves cooing on the feeders outside.