Several years ago our cat brought in a newly hatched baby quail. It was not injured and we set up a 10 gal aquarium for her. We babied her and she was a total pet. She would lay down in your lap and go to sleep. We named her Gizmo. I built an outside pen for her and she lived the 'life of Riley' for years. She was so incredibly tame. A male started coming and setting by her cage every morning. I left her door open because I knew she wouldn't leave. He would spend the day with her and leave about dusk. One day she did leave with him. I was happy because I thought ok they will go off and have a family and live happily ever after. On the third day I heard her calling from the backyard. My daughter walked out and Gizmo flew right to her. We put her in her cage and she ate for hours. I don't think she figured out how to make it on her own. Don't know what happened to Romeo...maybe he ran off with someone else.
Gizmo never left again and lived with us for about 6 years. She had the best life ever. We still miss her!
So in my opinion, they can live alone and do quite well.