The name Brent or Brant (US & orig.) goose, one of several "branta" species, comes from the old English (Viking) word for "burnt" in view of the black colouring.
The Brent goose has a white collar or neck patch and a white tail.
Some have side bars (and can look dark brown in sunlight).
There are 2 main subspecies of Brent goose, the "Dark-bellied"
("bernicla") Brent above, breeds in Siberia, winters in W. Europe,
and the "Pale-bellied" ("hrota") - breeds in Canada/Greenland, winters in US/W. Europe.
A third, lesser subspecies the "Black" ("nigricans") breeds in Alaska/ W.Canada/East Siberia and winters in the north Pacific Basin.
Brent following Cackling Goose
Brent goose (top left) with Cackling (top right), Lesser White-fronted (far right) and Barnacle geese
These similarly-sized Brent and Cackling Geese were constant companions.
The Pacific Black Brent/Brant
("nigricans") above and below