From Tetrapod Zoology.
That should tell you how big a trumpeter swan is.
Here’s a photo that can give you a better look at the size differences:
Trumpeter swans are giants. They can weigh nearly 40 pounds. It can have a wingspan of nearly ten feet.
That makes it the largest species of waterfowl in the world, and it is also the largest bird native to North America (domestic turkeys do not count.)