These are recognised as separate species by the American Ornithologists' Union and the IOC (taiga bean goose, Anser fabalis, and tundra bean goose, Anser serrirostris), but are considered a single species by other authorities, such as the British Ornithologists' Union.
[not verified in body] The related pink-footed goose (Anser brachyrhynchus) has also been included in the species complex.
In size and bill structure, it is very similar to Anser fabalis rossicus, and in the past was often treated as a sixth subspecies of bean goose.
Bean goose use courtship to find mates, including a display of tail feathers.
Some ornithologists (including AOU 2007) split them into two species based on breeding habitat, whether in forest bogs in the subarctic taiga, or on the arctic tundra.
The taiga and tundra bean goose diverged about 2.5 million years ago and established secondary contact ca.
The Taiga bean geese Anser fabalis fabalis wintering in Europe are considered to migrate across three different flyways: Western, Central and Eastern; which has been confirmed by stable isotope analysis of their flight feathers.