At a glance, tundra swans and whistling swans appear very similar. They are both large, white waterfowl with long necks and black bills. However, despite their similarities, tundra swans and whistling swans are actually two separate species.
Key Differences
There are a few key differences between tundra swans and whistling swans:
- Range – Tundra swans breed in the Arctic and subarctic tundra regions of Alaska, Canada, and Russia. They migrate south to spend the winter along the Atlantic and Pacific coasts. Whistling swans breed further south in the prairie pothole region and across parts of subarctic Russia. They winter predominantly along the Gulf Coast and southeastern Atlantic Coast.
- Size – On average, whistling swans are slightly larger than tundra swans. Whistling swans typically measure 46-59 inches long with a wingspan around 60 inches. Tundra swans are 44-51 inches long with a wingspan of 55-68 inches.
- Bill Color – Adult whistling swans have a black bill with a small yellow spot near the eye. Adult tundra swans have a completely black bill.
- Voice – As their names suggest, the two species have distinctive vocalizations. Whistling swans have a clear, whistling call. Tundra swans make a lower-pitched, resonant, wavering honk.
Taxonomy and Classification
Tundra swans and whistling swans are both members of the genus Cygnus in the family Anatidae. However, they are considered separate species:
- Tundra swan – Cygnus columbianus
- Whistling swan – Cygnus cygnus
These two swans were previously considered conspecific (the same species) under the name whistling swan or Cygnus columbianus. Based on differences in their size, bill color, vocalizations, and migratory habits, ornithologists determined they are better classified as distinct species. This splitting into two separate species was officially recognized in the 1950s.
Habitat and Range
The differences between tundra and whistling swans are reinforced by their generally separate breeding and wintering ranges:
Tundra Swan
- Breeding habitat – Arctic and subarctic tundra of Alaska and Canada, and coastal tundra of far eastern Russia.
- Winter habitat – Shallow freshwater and brackish wetlands along the Atlantic and Pacific Coasts of the U.S.
Whistling Swan
- Breeding habitat – Interior wetlands of subarctic prairies and taiga in Alaska, Canada, and eastern Russia.
- Winter habitat – Coastal marshes, lakes, and ponds along the Gulf Coast and southeastern Atlantic Coast.
There is some overlap, particularly in their winter ranges along the Pacific Coast. But whistling swans occur mainly west of the Rocky Mountains while tundra swans are more numerous east of the Rockies.
Physical Description
As mentioned above, tundra swans and whistling swans share many physical similarities but can be distinguished by subtle differences in size and bill color:
Tundra Swan
- Length: 44-51 inches
- Wingspan: 55-68 inches
- Weight: 14-21 lbs
- Plumage: Entirely white with black wingtips
- Bill: Black, often with small yellow spot near eye
- Legs and feet: Black
Whistling Swan
- Length: 46-59 inches
- Wingspan: 60-72 inches
- Weight: 16-27 lbs
- Plumage: Entirely white with black wingtips
- Bill: Black and yellow, yellow extends below eye
- Legs and feet: Black
The yellow marking on the whistling swan’s bill is more extensive compared to the tundra swan’s small yellow spot. However, juvenile swans of both species display variable yellow markings before achieving adult plumage at around 2 years old. Thus, bill color alone should not be used to identify species.
Behavior and Diet
Tundra swans and whistling swans share very similar behaviors and diets:
- Highly social, they forage in flocks and migrate in large groups
- Mainly herbivorous, feeding on aquatic vegetation
- Will also eat aquatic invertebrates, grains, and other vegetation
- Feed by dabbling in shallow water and plunging head underwater to reach vegetation
- Nest on mounds of vegetation on the ground near water
- Strongly monogamous, pairing for life
- Very vocal, emitting various calls and whistles
Aside from their distinct vocalizations, the two species exhibit almost identical behaviors in nearly all respects.
Population Status
Both tundra swans and whistling swans remain relatively abundant. However, tundra swans suffered significant population declines in the late 1800s and early 1900s due to hunting pressure and loss of wetland habitat. Their populations have since rebounded:
Tundra Swan
- Population: Approximately 100,000-200,000 individuals
- Conservation status: Least concern
Whistling Swan
- Population: Approximately 120,000-170,000 individuals
- Conservation status: Least concern
Both species can be legally hunted in most states, within specified harvest limits. Habitat loss is an ongoing threat, as their wetland breeding and wintering grounds continue to face drainage, development, and degradation.
Conclusion
While tundra swans and whistling swans appear very similar at first glance, they are considered separate species based on consistent differences in their size, appearance, vocalizations, and geographic breeding and wintering ranges. However, their behaviors and ecology are nearly identical. Both remain numerous and widespread across North America. While they may frequent the same wetland wintering grounds, tundra swans and whistling swans can be reliably distinguished with careful observation.
