Both trumpeter and tundra swans are large, white birds with unusually long and graceful necks. Rusty-orange staining on the feathers of the head and upper neck may occur when swans feed in lakes with sediments that are high in iron. The most reliable differences are found in their vocalizations and the appearance of their bills.
Trumpeter swan vocalizations are deep, resonant, bugle-like calls that are more nasal-sounding than tundra swans. Tundra swan vocalizations, on the other hand, are softer, higher pitched, and mellow woo-oo-woo calls.
To listen to and differentiate between a trumpeter and tundra swan call click here.
Adult trumpeter swans have black bills, though the pinkish red inside their mouth can sometimes be seen as a red line between the bills, seemingly giving them a “grin”. Tundra swans, on the other hand, have a black bill with yellowish pigmentation in front of the eye. The spot can be small and occasionally absent, but if you see yellow, you are likely looking at a tundra swan. Trumpeter swans have a more angular head and beak with the slope of their crown matching the slope of the bill, while tundra swans have a more concave bill profile. When looking at the junction of the beak and head between the eyes, tundra swans have a U-shape and trumpeter swans typically have a V-shape.
Not all big white birds are created equal! Southern Alberta is home to, or along the migratory route, of other larger-bodied white birds that might be mistaken for trumpeter swans at a distance or quick glance. Of course, trumpeter and tundra swans are the easiest to confuse, and although tundra swans are the smaller of the two species, size can be hard to discern when the two species aren’t right next to one another.
Snow geese are about half the size of swans, with pink bills and black wing tips visible when in flight. Swan bodies are entirely white in flight and adult trumpeter swans have a black bill. American white pelicans also have black wing tips visible in flight, but they will fly with their neck tucked back rather than outstretched. And the long yellow beak on pelicans is distinctive whether in flight or on water.