These two young swans just show you how varied young swans can be. IDing single young swans is a much overlooked problem with some giving off all kinds of signs leading you astray. Trumpeter and Tundra overlap in most ways even size and bill coloration. This particular Tundra has a large bill and head, and the head is not too rounded, putting out conflicting messages.

The pink on the bills of very young Tundra Swans usually touches the feathering at the base of the bill where Trumpeter rarely does. This pink is replaced quickly on some young Tundras, as on this bird, presenting black at both ends and pink in the middle as seen on young Trumpeter. The bills on immature birds tend to look larger than they do on adults because they are softer and still have to shrink and harden.

Note the bill here looks like it is just stuck on the large head where on Trumpeter the bill seems to engulf or try to eat the head.