Don't call me a silly goose

Left the unit to cycle home rather later than I had hoped, and feeling quite wiped after another day at the unit. As I started out from the hospital grounds into the Auckland Domain I saw a bunch of geese, mostly white. Standing out amongst them was a muscovy duck. Not that dissimilar in size, it is very different in colouration, and overall appearance. Why it is hanging out with the geese, I have no idea, and I presume its not because it thinks its a goose. However, I may be wrong about that.