The bill is heavy in proportion to head with a straight profile. Angular head shape somewhat resembling canvasback duck. Eye not distinct from bill.
Black bill with red border on lower mandible; the red border may be present on some tundras.
The bill is more dish-shaped in profile, bill smaller in proportion to head compared to trumpeter. Head smoothly rounded; eye usually distinct from bill.
The shape of the head profile may vary between individual birds. Tundra Swans especially, have a wide range of head-bill shapes, some having very obvious concave bills, while others appear straighter. Look carefully at the eye area for any yellow on the lore and to see if the eye is distinct from the bill.
Black bill, usually with yellow spot of varying size in front of eye; this spot maybe absent on some tundras. Mute—orange with prominent black knob at the base.
The bill is orange with a black knob at the base. A knob is clearly visible in both sexes but is more pronounced in adult males.
Less than one-half the size of a swan; total bill length is about 2"; bill is shorter compared to head length than in swans; bill does not extend very close to eye. Neck length is about the same length and distance from tip of bill to back of head. The bill shorter than swans, dark pink with black ‘grin patch’.
For more information on Snow Geese see Similar Species and Hybrids.