Budgie breeders who belong to either ABS or BAA, the two recognized national organizations that show English budgies in the US, use the word Sky as the general base classifacation for budgies that most of us think of as turquoise .
I found out early on not to fight the system and just memorize the word SKY.
The US standard is based on the standard used across the globe.
The last edition was published in 2012 by The WBO and may still be available through The U S organizations.
The last price I remember was around $12.00 US .
This is both a color and written description of the recognized stable mutations across the globe and is the standard used on the show bench.
Breeders of Americans and English that do not belong to these organizations often put their own names out for customers to identify a budgie which does not match the standard.
When you breed to a standard, you strive to produce a particular color mutation that is consistent all over the world. Breeders may have side projects mixing to produce non-standard mutations that are not recognized and at best show as an AOV any other variety.
People who seriously show to win use the standardized nomenclature.
Other breeders may try to put impressive names on their budgies to ask a higher price for special birds.
Registered breeders maintain registered stock and may also have stock of one or several new mutations that have not tested to the higher standard. The chicks that are sold at bird fairs are often the breeding stock that do not meet the organization standards. They are perfectly healthy but are often too small or have other faults not desired by the standard.
These birds are often quite lovely and often make wonderful companion birds though are not destined for the show bench. When a buyer approaches a breeder, the buyer should be clear on whether they wand a pet quality bird or a bird that meets show standard. Then the breeder will understand what the buyer is looking for.
When you contract for a budgie with a stated color it may take a while as the suggested percentages of genetic mutations are based on 100 % but budgies usually have no more than 6 clutches before they are retired.
So the possibilities are legion. Most breeders are split for the opposite color so a blue series bird
with a white face could also produce a normal yellow face green series or for example a class II yellow face violet which actually looks like a turquoise on the chest and deep cobalt/violet on the back. You ask where is the violet?
It is in the genetic history maintained bu the breeder. These are birds, that like the rainbow, are not always easy to produce.
It is always good to take an experienced breeder friend to help you chose your birds.
There are little tricks breeders can look for to suggest the heritage of a bird in question and which faults are superficial or important as a pet or as a show breeder.
We like to feel like breeders are honest , but the truth is "buyer beware".
Always check the leg band. Never buy a bird with any band date other than the current year or the just previous year unless you are looking for an older bird. which would have a 3rd year or older leg band.
Breeder leg bands have a lot of info that identifies the characteristics of the bird and may also return a lost bird.
Leg bands can also cause injury to the leg and need to be monitored for problems.
Best luck in finding your special baby, Jo Ann