Call of the trumpeter.

Authors(s): T. Wilkinson

Publication: National Parks

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Publication Date: 0000-00-00

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Abstract: Discusses efforts to increase the 'Rocky Mountain Population' of trumpeter swans. Factors which have caused the swan's decline; Declining population inside Yellowstone National Park (Idaho, Wyo., Mont.); Government relocation program; Trumpeter swan habits and behavior; Comments by swan biologist Ruth Shea of the US Fish and Wildlife Service and the Idaho Fish and Game Department; Impact of hard winters in the Greater Yellowstone area. INSET: Make way for trumpeters. Yellowstone struggles to prevent a swan song OF ALL THE BIRDS that inhabit the world's wetlands, swans most often appear in fairy tales and mythology. The snow-white birds have been used as poignant metaphors from the beginning of ancient civilization; even Socrates, prior to his execution in 399 B.C., spoke his last words about a swan singing its sweet rapture. But the song of North America's rarest swan--the trumpeter (Cygnus buccinator)--has not always had a storybook ending. For millennia, few members of the waterfowl family maintained a higher profile in North American flyways than the indigenous trumpeter, the largest waterfowl species in the world. A veritable jumbo jet of a bird, it flaunts a wingspan measuring over seven feet and a weight sometimes topping 30 pounds. In flight, the trumpeter has a regal charm; afloat, its graceful profile seems to harbor its own zen. Until the early 1800s, the trumpeter swan inhabited scattered wetlands from coast to coast and from northern Canada--where tens of thousands of swans used summer nesting sites--to the Gulf of Mexico, at the southern tip of the bird's winter range. As early as the 1700s, trumpeters had begun to disappear from the eastern half of the continent, and by 1900 the species was in serious danger throughout its range. Today, some six decades after Congress took emergency measures to save the trumpeter swan from extinction, the species maintains only a tenuous foothold in the West. Historians believe the swan's large size and low flights may have hastened the demise of the species. Hunters killed trumpeters for feathers for the plume trade and for meat. Records show that the Hudson's Bay Company--the major harvester of swans--traded more than 100,000 swanskins, most of them trumpeters, from 1820 to 1880. While commercial hunting was the primary factor in the species' decline, some scientists believe that destruction of wetlands also played a role. Because of trumpeters' characteristic loyalty-not only to life-long mates but to territory--they stubbornly home in on the same wetlands year after year. When those wetlands are destroyed or reduced in size, the swans continue to congregate at their traditional nesting and wintering sites, which become more crowded as habitat shrinks. Overcrowding results in loss of productivity, and some ornithologists say this is one reason the trumpeter is still on the wane. Survival of the few remaining trumpeters 80 years ago--members of a group now called the "Rocky Mountain Population"--was tethered to a small comer of the greater Yellowstone region. Here, the isolated warm waters in Yellowstone National Park offered sanctuary, according to Ruth Shea, a swan biologist employed jointly by the U.S. Fish and Wildlife Service and Idaho Fish and Game Department. The U.S. Biological Survey counted only 69 trumpeters there in a 1932 summer census, while 100 others were thought to exist at summer nesting sites in the vicinity of Grand Prairie, Alberta. Today there are more than 15,000 trumpeters in the world, and 75 percent of all breeding pairs outside of Alaska reside at least seasonally in the greater Yellowstone ecosystem. A migratory population from Canada joins resident trumpeters each winter in Yellowstone, at nearby Red Rock Lakes National Wildlife Refuge, Harriman State Park, and the vicinity of Grand Teton National Park, Wyoming. (Together, Yellowstone and Grand Teton boast the only flocks of trumpeters within the National Park System of the lower 48.) This winter concentration of resident and migratory swans is considered significant because it represents the best hope of restoring trumpeters to much of their former range. Red Rock Lakes National Wildlife Refuge, in Montana's Centennial Valley, was created in 1935 by Congress in response to the trumpeter swan's urgent need for protection. Then, as now, trumpeters were vulnerable to accidental shooting, ingestion of toxic lead in bullets and fishing jigs, poisoning, collisions with power lines, and human disturbance during nesting. Further, recent research shows that the production of trumpeter young, called cygnets, has been erratic--possibly because of overcrowded winter habitat or poor spring weather. Even with those liabilities, the swan population outside Yellowstone is considered stable when compared to birds breeding inside the park. Terry McEneaney, who spent a decade with the Fish and Wildlife Service before coming to Yellowstone as the park's ornithologist, says the park's resident colony of trumpeters is markedly dedining. "I don't mean to say that trumpeters will disappear completely from Yellowstone, only that visitors may encounter only migratory birds in the future," he said. Meanwhile, Shea, who wrote her master's thesis on swan reproduction in the park, says Yellowstone probably will never provide fruitful habitat for swans year-round. Ironically, Yellowstone was instrumental in rescuing the species, erroneously leading some to believe that reproductive conditions there were exceptional. "The park's role as a temporary autumn sanctuary far outweighs its value for producing swans that live there year-round," says Shea. "Now, during the autumn months when trumpeters are most susceptible to accidental shooting outside the park, Yellowstone continues to serve as a quiet refuge with high-quality food for hundreds of birds." Winters in Yellowstone are long and frigid, requiring birds to expend an enormous amount of energy merely to stay warm. Some waterways remain free of ice because of the constant influx of tepid water from geothermal springs, but these sites provide very limited amounts of aquatic plants, which are the species' primary food source. Shea says the shrinkage of habitat when Yellowstone Lake freezes explains why a massive exodus of birds from Yellowstone National Park occurs each December, when hundreds of migratory swans move west to ice-free waters in Idaho. Those trumpeters that endure the winter in Yellowstone emerge in the spring so weakened that successful nesting is unlikely to occur except in the mildest years. According to McEneaney, predation from coyotes and other scavengers also exacts a toll on nests, as does inclement weather and frequent flooding. Yellowstone's policy of "natural regulation," which prohibits rangers from interfering with natural factors no matter how detrimental, means the outlook is bleak for maintaining a year-round population of trumpeters in the park. "My hands are tied," says McEneaney. "But there are things we can do outside the park that have a positive effect on swans and their use of Yellowstone at other times of the year." Where is the trumpeter headed, and what is being done to restore healthy populations? A litany of factors is plugged into the survival equation, and each has relevance to the long-term protection of the species. The major stumbling block, says Shea, is persuading swans to leave their sanctuaries around Yellowstone and migrate once again to wetlands farther south. Simply, it requires biologists to help trumpeters relearn age-old migration routes. When trumpeters were extirpated from their vast former range a century ago, the surviving swans lost the knowledge of wetlands beyond the greater Yellowstone region. Shea says it is difficult for swans to broaden their winter range naturally if they don't know alternative sites. That is where Shea and Red Rock Lakes Refuge manager Dan Gomez come in. Unlike the hands-off management approach espoused by Yellowstone, habitat manipulation west of the park has taken various forms--some better than others, according to Shea. No setback stunned swan conservation more than the disaster of 1989 in Eastern Idaho. During the early weeks of February that year, when an arctic dry mass moved into the Yellowstone region, water along the Henry's Fork in Harriman State Park froze solid, cutting off a third of the Rocky Mountain flock from its main food source -- aquatic plants. As many as 100 trumpeters perished, forcing Shea and other managers to reassess the question of population stability. "As long as we have most of the trumpeters congregating in areas where their habitat is vulnerable and the food source is insufficient, as we do in greater Yellowstone, we are going to have problems," Shea concluded. "We also need to make sure that irrigators who own water rights on many of the key streams try to make accommodations for wildlife during the winter." To improve the birds' chances for survival, government scientists have designed an unprecedented trumpeter relocation program to expose swans to new locations, which ultimately could mean the reestablishment of migration to wintering sites farther south. In 1991 the U.S. Fish and Wildlife Service, in conjunction with the U.S. Forest Service and wildlife agencies from several western states, transported 354 swans-representing 17 percent of the wintering population in Greater Yellowstone-to lower stretches of the Snake River in Idaho, the Salt River drainage of southern Wyoming, and Fish Springs National Wildlife Refuge, Utah. The action came in anticipation of a record 2,300 to 2,400 trumpeters descending upon the greater Yellowstone region and a 75 percent decline in aquatic plants at Harriman State Park. After the trapping, a winter census showed 1,931 swans spread across different areas of the ecosystem. Displacing the birds from Harriman and Red Rock Lakes prevented their starvation, a potential crisis that could have made the 1989 disaster appear mild, Shea said. More significantly, it exposed trumpeters to other winter areas--and these swans, in turn, may introduce their cygnets to the territory in subsequent winters. By mid-March, wildlife biologists said the program appeared to be a success: fewer than 40 swans had returned to locations where they were captured. "It's a start," Shea said. "We won't really know if it works until next winter, but so far the reports have been favorable. We've had good dispersal and very few swans immediately returning." McEneaney and Shea speculate that if migratory swans can establish a presence in watersheds throughout Wyoming and Idaho, the species' range could rapidly broaden into Utah and Colorado and eventually link with restoration efforts in the Midwest. After being silenced for most of the 20th century, the familiar "koo hoh" call of the trumpeter may again be heard in potholes of the Great Plains as well. "The message of the trumpeters will be repeated each time these wild calls echo across the United States and Canada," Shea recently wrote. "As they pass overhead, they will continue to remind us that wildlife's future lies in our own hands. We have choices and solutions." Almost 2,400 years ago, Socrates said of swans, "You know that when swans feel the approach of death, they sing-and they sing sweeter and louder in the last days of their lives because they are going to that god whom they serve." But Shea holds a different view. "Socrates was wrong," she wrote, recalling the painful counting of trumpeter carcasses on the ice two winters ago. "The swans do not sing as they die. But in their fading gaze lies a simple and crucial message. In our modern society, the future of wildlife depends upon human wisdom and stewardship and our willingness to share the earth's resources." PHOTO CAPTIONS Trumpeter pair on Yellowstone Lake. A trumpeter pair with five cygnets on a family outing in Yellowstone. A researcher releases a trumpeter at Gray's Lake, Idaho. Government scientists designed the relocation program to expose the swans to new territory and ultimately to expand their range. A trumpeter defends the nest by lifting its wings in a "threat display". A nesting parent checks on her eggs during incubation. A young trumpeter, learning to fly, tests its wings. ~~~~~~~~ By Todd Wilkinson Todd Wilkinson is a free-lance writer based in Bozeman, Montana. He last wrote for this magazine on hard-rock mining in the national parks. MAKING WAY FOR TRUMPETERS Yellowstone National Park in 1991 will continue an aggressive program to aid the recovery of trumpeter swans, although biologists are focusing their efforts outside the park boundary. According to ranger-ornithologist Terry McEneaney, this summer park scientists plan to complete a live-trapping program aimed at removing exotic mute swans (Cygnus olor) from a strategic wetland 50 miles north of Yellowstone at The Call of the Wild Ranch in southern Montana. With the rapid increase in mute swans--whose numbers have grown from a single pair in the 1960s to 120 a few years ago at Call of the Wild-researchers fear these aggressive birds could invade the wetlands of Yellowstone and usurp habitat critical to the park's dwindling number of resident trumpeters. In place of the banished mutes, McEneaney and other biologists have begun transplanting pinioned (wing-clipped) trumpeters whose cygnets will be free to flee and interact with other wild populations. "What happens outside of Yellowstone is just as important for the trumpeter as what happens inside Yellowstone," McEneaney says. "It is important that we manage for the future of the species." PHOTO CAPTION Mute swan

Keywords: animal , bird, Aves, ornithology, swan, trumpeter swan, Olor buccinator, breeding, population, mortality, management, Yellowstone National Park, Grand Teton National Park, Snake River, Salt River, Star Valley, habitat, behavior, migration, Greater Yellowstone Ecosystem, Cygnus buccinator, Anatidae, waterfowl, water bird, hunting, human activity, Idaho, predation, canine, Canidae, Canis latrans, coyote, mute swan, Cygnus olor