I'm a new Sydney suburban duck owner of two gorgeous female Pekins.. or at least i thought they were females, but now I'm not certain about one of them! My girls are around 3 months old now, and my dad bought them together as cute little 1 week old's, as we were hoping for a source of unfertilized eggs and something for my nephews and nieces to pet when they come over. The larger and quicker to develop of the two is named Charlie with a bright orange bill, and the smaller with the pale peach bill is Sunny (or possibly Sonny now). As implied, both Pekins were almost certainly showing signs of being female due to their flat tails and loud distinguished 'QUACK'! However over the past couple weeks, Sunny's voice has lowered to a kind of dull chirp or squawk, a small 'flick' feather has appeared on her tail, and during the past two mornings has decided to begin 'pecking' and mounting her sister during their morning bath. I found this pretty odd when i first noticed the change in behavior because Charlie was always the more dominant and 'brave' of the two girls; Sunny would always follow her around like a chick would with her mother, and fret terribly when she was separated. Charlie is also more comfortable being stroked, picked up and hugged whereas Sunny has always been rather timid and fearful of me reaching out for her. I'm guessing either that Sunny is actually a drake, or she is assuming role of the 'dominant' to make up for the lack of a male, now that its approaching winter in Sydney and both girls are reaching maturity. But i was wondering if anyone had some advice or answers about the situation? My folks don't really want any more ducks, so im really hoping this mating ritual is just a phase! Shake your tail feather: Sunny (left) and Charlie (right). Its not a perfect 'Drake Curl' but is it a baby version? Sunny assuming dominance while Charlie goes with the flow. Sunny having a little chat, with Charlie interrupting at the end; notice the difference in pitch of their voices.