The Yellow feather is a smaller feather and the colour is more intense and colour in the feathers goes right up to the edges of the feather.
Tag: Feather Types
An intermediate feather is a combination of both yellow and buff and is preferred for show budgerigars as it gives the appearance of a larger birds while still retaining good condition and colour.
Buff feathers are coarse in appearance because they are wider and longer than yellow feathers. They tend to look untidy even when the bird is in condition. They can make a budgerigar appear much larger than it really is.