They have a black head and neck with a distinctive white "necklace" or patch on the sides of the neck.

Unlike most terrestrial geese, the Brant is a "sea goose" almost exclusively associated with coastal marine environments. Brant Overview, All About Birds, Cornell Lab of Ornithology

Their backs and wings are typically dark gray-brown, while their under-tail and vent areas are pure white. Subspecies Differences: