Mute swans are beautiful but are considered a “nuisance species” in the United States. (Ann Cameron Siegal)

Throughout literature and dance, swans are the symbol of grace and beauty. Surprisingly though, some real swans are seen as harmful to the environment.

Hmmm, how can you not love a swan? Read on.

There are three basic swan species in North America: tundra, trumpeter and mute. Some weigh more than 25 pounds and have wingspans of more than six feet. They’re huge birds!

Tundra swans, the smallest of the three types, nest in Alaska or the Arctic and then spend the winter in our area. Trumpeters nest in northern areas including Ontario, Wisconsin or Minnesota and occasionally show up around here in the winter.

Mute swans live in the Chesapeake Bay area, among other places, year round.

How do you tell them apart?

While adult tundra and trumpeter swans look similar — all white with black bills — their subtle physical differences may require binoculars to see. Trumpeters often have a bright reddish “grin line” along their lower jaw (the mandible) that makes them look like they just heard something funny.

Tundra swans are smaller than trumpeters and usually have yellow spots on their lores — the space between a bird’s eyes and bill on each side of its head.

But the easiest way to tell tundra from trumpeter swans is by the sounds they make. Trumpeter swans sound as if they are tooting a horn. Tundra swans have a high-pitched honk, similar to a goose. The calls of both can be heard a mile away.

Mute swans are the easiest to recognize because of their orange bills with a black knot on top. A mute swan can also bend its neck into an “S” curve.

Although “mute” means silent, these swans do make hissing and snorting noises when threatened. You might also hear something like a puppy’s bark.

The controversy

Mute swans are not native to North America. They were brought from Europe in the 19th century.

While these beautiful birds are the national bird of Denmark and are protected in Britain, they are considered a “nuisance species” in the United States. They are very aggressive toward other waterfowl and pull up underwater grasses that create protective habitats for fish and crabs in the Chesapeake Bay. Once numbering in the thousands in Maryland and Virginia, only several hundred mute swans remain because of state efforts to decrease their population. The debate continues over whether or how to limit the mute swan population even more.

Still, it’s hard not to gaze in wonder when you see one gliding across the water.

— Ann Cameron Siegal