https://www.fws.gov/rivers/species/cygnus-columbianus-columbianus-cygnus-columbianus-columbianus
Cygnus columbianus columbianus (Cygnus columbianus columbianus) | U.S. Fish & Wildlife Service
cygnus columbianusfishwildlifeservice
https://www.usgs.gov/publications/delineation-tundra-swan-cygnus-c-columbianus-populations-north-america-geographic
Delineation of Tundra Swan Cygnus c. columbianus populations in North America: geographic...
North American Tundra Swans Cygnus c. columbianus are composed of two wellrecognised populations: an Eastern Population (EP) that breeds across northern Canada...
in north americatundra swan