I've housed many species of quail (including Gambels) in mixed flights and aviaries. I raise mostly finches and doves and haven't had any issues with aggression. Right now I have 6 coturnix housed with about 30 Zebra Finches, 2 diamond and 2 white winged doves in an 8 X 8 walk in aviary. They all get along great. Just keep a close watch on any new birds you add to the mix! Even though they SHOULD get along, you never really know until you actually house them together. I have a diamond dove that can't be in the same cage with anything...they're usually very passive, this guy didn't get the memo...he'll chase any bird I put with him to the point of exhaustion. So again, there are plenty of other species you could put with your quail, just watch them VERY closely for a good while.