The baby is double factor because both parents are spangles.
The only other solid yellow birds are:
a. lutinos -- which have red eyes
b. dark-eyed clears -- which have plum eyes
c. golden-faced albinos -- red eyed and hard to tell from lutinos.
Yellow budgies have faint markings and aren't solid yellow.
Wow her (or his) colours certainly are impressive. Since I have been here, Budgies have grown on me actually. I used to sort of just pass by them in stores without taking any notice before, but now I like watching them! I'm a changed person.