Parakeets describe all sorts of little birds that are not actually parrots.
http://www.budgies.org/
The above link has a picture of a blue budgie on it. They come in all different colours, although I believe yellow and green is the standard that all wild budgies are, the variety of colours in the pet class are mutated genes, similar to our cavies.
I have no idea about the content of the above site, I just grabbed it off google.