Flying swan identification:
The trumpeter neck is actually proportionally longer than the tundra
compared to body length. And the bill of the tundra in flight looks like a
black blip stuck on the side of a styrofoam ball. The Trumpeter looks like
the black bill is a cone coming over part of the white ball. Of course, it
always helps to have the two species together for comparison and hopefully
they will tell you by voice what they are.
Also, juvenile trumpeters are very dark compared to tundra - however this
is subjective at this time of year. Becomes more diagnostic in January as
the tundra juveniles get more white feathers.

Martha Jordan