Yes, Liz, that site says creamino is a sex-linked gene in Shaft-tails, really much easier than trying to figure out Gouldian genetics!
Your normal male paired with a creamino hen will produce:
100% normal males split/creamino
100% normal hens
Then if you take one of those split/creamino males and pair it with a different creamino hen, you will get:
50% creamino males
50% normal split/creamino males
50% normal hens
50% creamino hens
Or, if you take one of those split/creamino males and pair it with a normal hen, you will get:
50% normal males
50% normal split/creamino males
50% normal hens
50% creamino hens
Once you have a male creamino, you can pair it with a normal hen and you will get:
100% normal split/creamino males
100% creamino hens
The last combination is creamino male with creamino hen, you get:
100% creamino males
100% creamino hens
This pairing is the only one where you will get all creamino babies, but it is also the least desirable, as the babies can go down in size, color, health, etc.
Don't get hung up on the percentages, they refer to the average of a huge number of pairings, just used to give you an idea of what you may expect. For example, my pairing of normal split/fawn male with fawn hen produced two babies, both fawns (sex unknown at this time). I could have had normal split/fawn male babies and normal hen babies too if I'd had a large clutch.
Each combination will produce babies that will be easy to figure out, except for the normal split/creamino male with a normal hen. There you will get males that are normal and males that are normal split/creamino, and there will be no visual clue as to which is which. All you can do then is breed them and their results will tell you what they are!
Remember:
Males can be normal, normal split/creamino, or creamino
Hens can only be normal or creamino, there is no such thing as a split in a hen when it is a sex-linked mutation.
This was all researched and explained to me by rayray, when I was confused as to what to expect with the fawn Owls.