Aust yellow back gouldians

[Tass]

Hi guys

I know this topic has kept popping up, I've looked at previous post on this subject and I thought I was getting it but then it just turned upside down.
when i bought my birds I was one of those people that got "those pretty yellow birds' , now I know there's 2 different types of mutations so need help.

I have attached 2 photos (first time tried this).

The greenback has a white bib and person said this means he's split to white breast. He also has a yellow smudge on the back of his head,
The yellowback , when I bought him had green also on his back but that mostly molted out. Around the area around his face is all white , NO grey or blue.

I dont want to cross mutations, I know these are both cocks , I have a yellowback female.

i think they are AYB

[Tiaris]

The pale flecks usually indicate that the bird is split to Australian yellow.

[Tass]

Thanks Tiaris , is that also how you ID the yellowback as AYB and not EYB , the paleness on the wings , flights or the whiteness around the face.

[Tiaris]

Many (but not all) Australian yellows have green streaks around the back/nape area. Euro yellow only have clean yellow and white throat on double factor males. Single factor males have unclean yellow on the back and a grey throat. A white breast is a separate mutation when appearing on a Euro yellow whereas Australian yellow exhibits a white breast without carrying the white-breasted mutation. If a white-breasted, yellow-backed bird is bred from green backed parent(s), then it is very likely Australian Yellow (recessive). Euro yellow is a dominant mutation so green birds cannot be split to it. Further, if yellow-backed, white breasted birds appear in aviaries/flocks containing flecked splits as shown in the pic, Aust yellow is most likely.