Hi all! I've had Luna since early June 2015 and had been told that Luna was a female. Supposedly she was about 6 months old or something. We originally bought her as a friend for our tame male cockatiel, Milo, but unfortunately he flew away during that same month. On her own, Luna began singing to herself, imitating the native birds and learnt the phrase "pretty boy" and "hello boy", as well as various short songs from Milo. Under the assumption that she was a female, we bought another two definite males and a possible female as companions for Luna. Our family friend who breeds cockatiels thinks Luna may actually be a male due to the lack of barring on her tail. I've been researching to try and visually sex Luna, but she contradicts a lot of things the internet tells me. Basically to summarise Luna: - Sings and whistles to herself when alone. - Rarely but has once or twice sung to herself even in the presence of new cockatiels, but does so alone (no heart wings and away from others) - Does the upside thing where she hangs upside down and opens up her wings - Though semi-tame (can step-up, sit on shoulder, feed from hand, etc.), still hisses and bites. - Isn't interested in mirrors. - Screamed/screeched a lot in the evening (i.e. when Milo went hiding in his box or when she was hungry)-- over the past few days she screamed a lot even when we gave her attention, food, toys, etc. so that was when we decided to buy her some friends and now her screaming has stopped. Even when Milo was around her age, he already portrayed a lot of masculine characteristics such as heart-wings, whistling to mirrors, attached to mirrors, vent rubbing on toy, jumping randomly, etc. I think she's a grey split to pied. Not sure if the pictures help, but in her cheek patches there a streaks of grey. Tried the pendulum test for fun and before she started chewing the shiny metal, there was more of a circular movement than up and down. I also don't know/remembered if she went through her first moult or not. Is she still too young? Help. Thanks in advance!