By March Mahr
The Trumpeter Swan (Cygnus buccinator) is the largest waterfowl in North America and the largest swan in the world. Yet there’s more than their size to blow a horn about—Trumpeter Swans are making a comeback. Once abundant and widespread within a wide band extending from Alaska along the Pacific Coast to the Midwest in the U.S., and throughout western Canada, Trumpeter Swans were nearly extinct by 1900. Both their numbers and their distribution were severely reduced by extensive market hunting, the commercial plumage trade, and widespread loss of wetland habitat. The only Trumpeters that survived were those that lived year-round in remote areas or whose traditional migration patterns avoided areas of human settlement. Decades of conservation efforts have rescued the Rocky Mountain Trumpeters from near extinction, creating a conservation success story. Trumpeters breeding in the Greater Yellowstone Ecosystem have responded well to international restoration programs, growing from only 69 birds remaining worldwide in 1932, to nearly 500 in recent years. These birds are joined each winter by an additional several thousand Trumpeters from western Canada to form the Rocky Mountain population of Trumpeter Swans.
In 1993, I was first introduced to the grace and bravado of Trumpeter Swans when I spent a summer conducting field research at Red Rocks Lakes National Wildlife Refuge in the Centennial Valley of southwestern Montana. I was frequently distracted from surveying plants by a sharp bugle announcing the arrival of Cygnus Flight #756. With wings spanning up to eight feet, and both neck and legs fully extended, Trumpeters are powerful flyers capable of speeds up to 50 miles per hour. I also enjoyed watching flotillas of swans and their cygnets (young of the year) bobbing on the shallow lakes of the refuge, swimming with their necks erect in regal beauty.
Red Rocks Lakes National Wildlife Refuge was established in 1935 specifically to protect Trumpeter Swans because nearly half (i.e., less than 40 birds) of the Trumpeter Swans known to exist were found in this area. Today, the refuge continues to be one of the most important habitats in North America for these majestic birds. Over the years, the Red Rock Lakes refuge flock has served as an important source of breeding birds for reintroduction efforts in other parts of the country. You may be thinking, “Brrr! Isn’t the Yellowstone area freezing in the winter?!” Yes, it can be a frigid place; yet the area’s system of warm springs provides year-round open waters where Trumpeters find food and cover even in the coldest weather.
Trumpeter Swans must remain near open water to obtain their preferred diet of aquatic plants. Their staple diet includes waterweed, pondweed, water milfoil, and duck potato. A mature adult will consume up to 20 pounds of wet herbage each day! They also feed occasionally on grain, seeds, freshwater invertebrates, snails, and worms. Trumpeters have broad flat bills with fine tooth-like serrations along the edges that strain water when they eat aquatic vegetation. They use their strong webbed feet to dig into the pond or lake bottom for roots, shoots, and tubers, then plunge their heads and necks underwater to eat what they have dug up. Their long necks and powerful bills allow them to reach down three to four feet and pull up roots and stems other birds can’t reach.
Aside from Trumpeters, there are two other species of swans in North America: the native Tundra Swan (Cygnus columbianus, formerly known as the Whistling Swan); and the non-native Mute Swan (Cygnus olor), a Eurasian species that has been introduced or escaped from captivity, and now breeds in several parts of North America.
This spring on Smith Lake, I saw several big, white swans. Trumpeter? Tundra? Since Trumpeters often mix with flocks of the more common Tundra Swan during migration, I consulted my field guide. Following are a few tips to help with species identification:
Trumpeters are much larger than Tundra Swans but both are huge birds and size differences may be difficult to distinguish unless the two species are side by side or seen at close range.
Their call is a sure method of species identification if you’re lucky to hear it. Trumpeters have a loud, low-pitched, hoarse, bugling call of hurp or hur di di, which D.A. Sibley likens to the honk of a European taxi. Tundra Swans have a high-pitched, quavering, melancholy klooo or kwooo with an accentuated oo-oo-oo sound, and a hooting or barking quality that may sound like ‘whoops’ from a distance.
Head and Bill:
This spring when a big white bird’s in view, be sure to look carefully at the edge of the bird’s lower mandible for a red border or stripe of lipstick; check the eye area for any yellow on the lore; and see whether the eye is distinct from the bill or is contained in the black mask of the face. At a quick glance you should be able to see the size and position of a Tundra Swan’s eye easily, while that of a Trumpeter is more hidden. Happy birding!