Wattle (yellow faced blue boy) & Daub ('normal' blue girl) are brother and sister best friends, just four months old. You've already met thier big sister Greywing, and little brother Napoleon.
Still very camera shy, they spend the whole day together in a world of thier own. Yesterday I watched them play 'keep away' with a twig. One would pick up the twig in thier beak and run, the other chasing behind. When the chaser caught up, there would be a brief tug of war, with the winner of that becoming the runner for the next round.
Since they are near inseparable, I thought it would be nice to name them something that went together. Hook & Ladder? Peanut Butter & Jelly? Wattle & Daub? Sure, why not!