Hey there. I'm assuming you are referring to the budgerigar affectionately known as budgies but most commonly called "parakeets." I've found some links to answer your questions about the color variations in these sweet pets!

drawings of the various colors
http://www.geocities.com/budgie-place/p_colors.html

"Although the Budgerigar in the wild is usually a green, yellow and black bird, the Budgerigar breeders have come up with a rainbow of colors to enjoy and puzzle over."
http://www.globaldialog.com/Adventur...iel/color.html

"Budgerigars come in a wide range of colors. The Light Green is the natural, wild color. In captivity, where predators are not a concern, color has no bearing on health or disposition. It's a myth that the Albinos and Lutinos (all white and all yellow, both with red eyes) are blind or suffer from extremely diminished vision. I've kept both in walk in walk-in cages with lots of other Keets. Some of the other popular colors are Blue, and the several forms of Pied (splashed-colored). There is also a Crested mutation of the feathers of the head. These birds seem to possess the same Beatle hair-do as the Gloster Canary, though the genetics are completely different."
http://www.petbird.com/faq/budgie.htm


OK, thats all I've got! Enjoy ~ Kate