Three different species of Brant Goose are distinguished, which are sometimes also regarded as subspecies.
Two species occur in the US: the Pale-bellied Brant Goose and the Black Brant Goose.
Dark-bellied Brant Geese breed in Siberia and winter in Northwestern Europe

The "Pale-bellied Brant Goose", breeds on Spitsbergen, Greenland and in Northeast Canada.
These Pale-bellied Brant Geese mainly winter in Denmark, the east of England and Ireland and the Atlantic coast of the United States.

Black Brant Geese breed in northeastern Siberia, Alaska and northwestern Canada and winter on the west coast of the United States.
What is immediately noticeable in Black Brant Geese are the bright white flanks that contrast strongly with the dark back and belly, both of which are clearly darker than in the other two Brant Geese species.
Another characteristic is the white spot on the neck: it is more extensive in the Black Brant Goose than in the other two species and often closes almost like a collar.

Jamaica Bay Wildlife Refuge, Queens, New York City, New York, USA, 5 May 2014