Hi,
I'm confused over the identity of this bird. The yellow on the facial skin should mean it's a Tundra Swan.
However, this bird is tagged, and as far as I know they only tag Trumpeters. Also the facial skin near the eye is almost as wide as the eye, which is a character for Trumpeter. Did you happen to notice any significant size difference between this bird and the Trumpeters?
Regards,
Thomas