https://www.backyardchickens.com/threads/silver-appleyard-versus-snowy.308832/
Post from the above linked thread:
"In the US, in bantam ducks, the following all have the Snowy color- Silver Bantams (what are sold as "Mini Appleyards"), Snowy Calls, and Snowy Mallards. They all look very similar. I breed both Mini Appleyards and Snow Mallards and honestly some of them look identical. There are small differences in size in all the birds, but there are a lot of birds that blur the lines. There are differences in temperament as well. My Silver Bantams/Mini Appleyards are some of my quietest, calmest birds and are in general a little more Call in type than the Mallards (they were developed from Calls so that makes sense). The Snowy Mallards, in general, are a little louder and some are a little more rambunctious. A lot are also more "racey" and streamlined in appearance, but you lose that trait very fast if you don't breed for it. The Snowy Calls, obviously if they are good quality, have a different body type and should be louder. Again though, I'm sure you could find birds of all three varieties that look identical unfortunately.
None of the birds above are true Silver Appleyard color (Silver and Silver Appleyard are different colors). In Europe, they do have Mini Silver Appleyards that are light-phase restricted mallard. In the US, we don't (or they are not at all common). As Mrs. Turbo said, there are also Silver Appleyard Calls. I have some, but I haven't done breeding tests yet and don't know their genotype, but they do look a lot more like the full size SA, than the US Minis do. In the US we also have Green Head Australian Spotteds, which are light phase Mallard, and can look almost identical to full size SA (
editing to add- I mean that the ones that are light phase look like SA. The Aussies *should* though be bred for harlequin phase. If you breed two heterozygous harlequin phase together, you will get 25% light phase, hence the birds that look like SA.). Having bred them for several years now, I strong suspect that some of the Aussies also carry restricted Mallard genes. As it is, it is well known that there are
at least 9 different genotypes for the Australian Spotteds depending on whether they have blue or not and are harlequin phase or light phase.
Anyway, I know this is probably the most confusing set of colors/breeds in the US ducks. Once you understand though the basic differences and how the breeds were named, it is easier to understand.
The biggest difference between the birds that are the harlequin-phase dusky "Snowy/Silver" and the ones that are light-phase (or harlequin phase) wild type is the eye stripes and head coloration. If the bird has no eyes stripes and a shaded head, they are dusky based and therefore Snowy/Silver. There are other differences as well, but that is one of the easiest discerning factors and I know this post is already becoming a book." Post #12
Silver appleyard call duck pic post #40.