The thing way more interesting about swan vs duck is which one imo.
For swans its quite clear cut, while the muted swan might be the most iconic one the black swan would defenetly have the most value, doing everything the mute swan can whild being just as common and from Australia.
Ducks feel much more context sensitive as especally ducks have a good choice for most potential packs and i doubt most people dont care to much if its a mallard, mandarine, wood or white faced whistling duck, not to mention all the other duck species that are common in zoos with all of them having their own advantages, mallard being standard duck, mandrine the most iconic pretty duck, wood offering a very different looking one for north america and white faced whistling being found in tropical south america, africa and madagascar giving some feathery love to many different regions.
Id argue all 4 wouldnt invalidate one another and be the bare minimum duck representation and comeone frontier duck pack when?
So if we get just one of these six black swan would props be best but really all of them are must haves for the game