I think no,
Lilly = Swan, Swan = White, Bernhard = Green, Greg = Swan.
Color of Swan or Greg = White
Lilly = Swan, Swan = White, Bernhard = Green, Greg = Swan.
Color of Swan or Greg = White
it likely that it's white but there is no way to know for sure.
Australian black swans are black, but chicks are light grey:) Lilly could be chick while Greg could be adult Australian swan