Almost all adult tundras have a yellow spot in front of each eye, something rarely found on a trumpeter. The trumpeter swan closely resembles its smaller relative, the tundra swan, but trumpeters have a red lipstick-like line on their lower bill and usually lack a yellow spot near the eye. The two species can more easily be distinguished by their calls. This is reflected in the shape of its throat. While the tundra swan's trachea is long and convoluted compared to our straight tube, the trumpeter's instrument is even longer and possesses an additional loop.
Trumpeters hold their necks vertically, frequently with a kink near the base.
The historic loss of trumpeter swans in California mirrored trends throughout the continent. While trumpeters once numbered an estimated 100,000, they rapidly disappeared after European settlers arrived. The swans were largely exterminated along the eastern seaboard by the 1830s. Populations in the rest of the continent dropped quickly as well, thanks in no small part to the Hudson's Bay Company, which traded in trumpeter skins obtained in the heart of the Canadian breeding range throughout the 1800s. Swans were not just eaten.