| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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| Feature Herald Swans' Reprise Ko-hoh! Ko-hoh! Like royal heralds, trumpeter swans announce their arrival. After an absence lasting nearly a century, Cygnus buccinator is once again flying high over California's winter wetlands. Once a common sight in the northern part of the state and in the Central Valley, they were nearly wiped out here and in most of North America by the early 1900s. But a variety of protective measures have brought them back from the brink to number nearly 20,000 worldwide today. Trumpeters have been dispersing from their strongholds in other states and Canada and could one day become a frequent sight in the winter sky. Winston E. Banko documents the earliest swan sightings in his epic 1960 study of trumpeters. He cites naturalist J. S. Newberry, in 1857, as the first to observe them in California. A. L. Heerman recorded them a few years later in the Suisun and Sacramento valleys and found them for sale in San Francisco markets. By the early 1900s, the record is silent, and in 1928 the California Division of Fish and Game declared that "the trumpeter swan, once common, is now one of the extinct species of game birds in California." A few more sporadic sightings were reported over the years: one in 1935 and one in 1957, both in Lassen County, and then several more identifications--many unsubstantiated--in the 1960s. Trumpeters traditionally nested in Alaska, Canada, and much of the northern United States, journeying as far south as Mexico and to both coasts for winter feeding. While few dispute that trumpeters once wintered in California, the conjecture that they ever summered--and nested--here is more controversial. Ruth Shea is one biologist willing to climb out on that limb. President of the Minnesota-based Trumpeter Swan Society, Shea is regarded as the nation's foremost expert and staunchest defender of trumpeters. Since her graduate-student days at the University of Montana in the mid-1970s, she has devoted herself to the study and preservation of trumpeters and has led U.S. Fish and Wildlife Service efforts to restore their populations. Shea believes that trumpeters bred in California long before Europeans arrived, something that can neither be definitively proven nor refuted. "After all," she speculates, "why wouldn't they have nested here long ago? They nested in comparable latitudes elsewhere in the United States, even as far south as the Carolinas and possibly northern Florida. We know early North Americans contributed to the loss of several large mammalian species. It is certainly conceivable that they also impacted this "mammoth" of the bird world." Archeological evidence around Utah's Great Salt Lake and in other regions of the country indicate that Native Americans made use of trumpeter swans, probably for food. Shea thinks it is likely that Native Americans who settled in California thousands of years ago killed swans as well. Few sources of meat were so readily obtainable. Trumpeters tend to fly low and move slowly on land. They defend their nest by facing the attacker and spreading their wings wide. When they molt their primary flight feathers each summer, they are unable to fly and, Shea claims, "become sitting ducks for anyone with even a primitive weapon." Such easy picking, she says, may have diminished the swans' distribution patterns even before the arrival of the Europeans, causing trumpeters to confine their sojourns to California in the winter rather than to stay year-round. Weighing up to 35 pounds, trumpeters are among nature's heaviest flyers. Their eight-foot wingspan, pure-white feathers, and loud sonorous calls make a stirring impression. Trumpeter swans and the somewhat smaller tundra swans are North America's only native swans. They look alike, with pure white feathers and black bills and feet, and often travel together. Experts can pick out subtle differences in their bill shape, or the red lipstick-like line on the lower bill of most trumpeters. Almost all adult tundras have a yellow spot in front of each eye, something rarely found on a trumpeter. The two species can more easily be distinguished by their calls. The tundra calls with a distinctive "woo-woo-woo," while the trumpeter's resonant vocalization sounds just like its namesake. This is reflected in the shape of its throat. While the tundra swan's trachea is long and convoluted compared to our straight tube, the trumpeter's instrument is even longer and possesses an additional loop. Trumpeters hold their necks vertically, frequently with a kink near the base. The historic loss of trumpeter swans in California mirrored trends throughout the continent. While trumpeters once numbered an estimated 100,000, they rapidly disappeared after European settlers arrived. The swans were largely exterminated along the eastern seaboard by the 1830s. Populations in the rest of the continent dropped quickly as well, thanks in no small part to the Hudson's Bay Company, which traded in trumpeter skins obtained in the heart of the Canadian breeding range throughout the 1800s. Swans were not just eaten. Their skins were turned into powder puffs for European ladies, their down stuffed pillows, and their pure white feathers were cherished for hats and quill pens. John James Audubon preferred swan quills for drawing fine detail, noting that they were "so hard, and yet so elastic, that the best steel pen of the present day might have blushed, if it could, to be compared with them." Swans were actively protected after 1918, when the federal Migratory Bird Treaty Act made shooting them illegal. A decade later, the Migratory Bird Conservation Act of 1929 authorized the acquisition of land for waterfowl refuges. This move was as important to the swans' ultimate survival as the hunting ban. By 1933, fewer than 70 wild trumpeters were believed to exist, and few ornithologists doubted their ultimate extinction. All were winter residents of remote spring-fed areas in and around Yellowstone National Park. This normally inhospitable winter habitat--where frigid air temperatures dip below -50 degrees F--offered refuge to the remnant population. Swans survived because thermal springs kept open water available throughout the year in areas so isolated that hunters couldn't find them. The best news observers of the dwindling trumpeters could ask for came in the early 1950s when a Pacific Coast population of several thousand was discovered during aerial surveys near Alaska's Copper River. These birds summer in Alaska and migrate south in winter to coastal areas of Canada and Washington. This vigorous population has grown steadily since its discovery and is now estimated at 16,000 swans. A few have made their way into Oregon and are now coming into California. The infrequent trumpeter seen in California in the 1930s and 1950s probably came from this population. Most trumpeters now entering California appear to come from the Rocky Mountain population. This once-tiny population, clustered around Yellowstone, has grown over the past 60 years, increasing to about 3,100 birds. Reducing illegal shooting, protecting habitat, controlling water flows in dammed areas, and supplemental winter feeding brought this population away from the brink. Most of these swans migrate to Canada for the summer, but about a quarter of them stay near Yellowstone year-round. Shea recognized the danger in such a concentration of swans; one massive freeze or disease outbreak could devastate them. They lived in an artificial Eden specially stocked with grain to see the swans through each winter. Furthermore, the unnaturally large population of swans degraded the habitat for fish and other waterfowl. "The problem was not that there were too many trumpeter swans, but that there were too many in one place." says Shea. "We had all our eggs in one very shaky basket." She realized that the next step in effectively managing the birds was to disperse them. Swans once migrated to many other wintering areas, after all, but those that went farther south had been hunted, and those that stayed had been fed. The population no longer knew where else to go. Teaching swans to migrate, however, is trickier than merely cutting off their food supply. Swans learn migration routes from their parents. Juveniles, or cygnets, stay with their parents the first winter, fly with them to feeding sites, then join them on the flight home. Soon afterward, the parents drive the young away. Trumpeters begin breeding at age two to six years and may live 20 years or more, returning to the same wintering sites each year. State and federal agencies have tried to disperse the flocks from unsuitable sites in the Yellowstone area by "hazing," or shooing birds away with loud noises, and by trapping and transporting swans to Idaho, Oregon, Wyoming, and Utah. The latter technique, in which captures occurred at night in an icy river, has been deemed unnecessary because hazing has met with success. Some swans relearn migration routes to historic wintering areas, while others return to familiar ground near Yellowstone. In 1996, about one quarter of the Rocky Mountain trumpeters wintered outside the core area near the national park, making that population's recovery more secure. Since 1986, some swans have flown as far as California. Some in California have also proposed actively bringing trumpeters into the state, though not without opposition from some states' Fish and Game agencies. One indication of mixed feelings is that trumpeters are not among the listed threatened or endangered bird species in California, though the California condor is probably the only native bird that is more rare. Dave Paullin, a biologist with the U.S. Fish and Wildlife Service, says, "Biologically, it makes sense to bring them here. California is a banana belt! It rarely freezes and there's tons of groceries." But Paullin understands the position of his opponents. With so many already-classified endangered species competing for funding, many question, "Why bring on another headache?" Although trumpeters are not on the state or federal endangered species list, they are protected under the Migratory Bird Treaty Act. A hunter who shoots one, even mistakenly, may be cited for poaching. Encouraging trumpeters to come to California would require more monitoring, and a future threatened or endangered listing would demand even greater efforts to protect them. Resources would have to come from other state wildlife programs already on a shoestring budget. The migration of trumpeters to California affects the Departments of Fish and Game in other states as well. The Pacific Flyway Council, with representatives from state and federal management agencies and hunting and conservation groups, recommends regulations to the Fish and Wildlife Service for the hunting of migratory birds in western states. While it is illegal to shoot tundra swans in California, they can be hunted in parts of Nevada, Montana, and Utah. When trumpeters fly to California from the Yellowstone area, they are likely to be confused with the look-alike tundras and may be accidentally shot. In fact, some trumpeters have already been killed. Current law allows a small but strict quota of "incidental take" of trumpeters; if this number is surpassed, tundra swan season must be shut down in order to protect the trumpeters. Shea and the Trumpeter Swan Society are observing the quota system closely, but it remains unclear whether trumpeters will be adequately protected as they attempt to rebuild old migratory routes. Flyway Council meetings frequently address how best to protect the trumpeters, including adjusting the swan hunting seasons to reduce the likelihood of their being shot. California Fish and Game officials also worry about avian cholera. This fatal disease occasionally plagues snow geese and tundra swans in the Central Valley. Why put a rare species at risk for this disease, some argue, and take the chance that swans will migrate back to Yellowstone and infect the rest of the flock? According to Shea, though, birds that contract avian cholera are likely to die while still in California before they have the chance to migrate back to their summer grounds. Furthermore, she points out that while bringing trumpeters to California will undoubtedly increase the risk of individuals dying from disease, from hunters, and even from crashing into power lines, the advantages of dispersion far outweigh the risks that the population now faces as it concentrates in marginal winter habitat. Even without official encouragement, though, trumpeters are finding their way to California, hitching rides with migrating tundra swans. A few years ago, Shea came to California and spent a week searching for trumpeters among tundra flocks. She found about 20 of them, but thinks there may now be a few hundred scattered in the Sacramento Delta and Central Valley. One pair even summered in northern California the past few years, a good indication that trumpeters may soon breed in the state. Farmers Sally and Jim Shanks have helped lead efforts to create good wetland habitat out of farmland in the Sacramento-San Joaquin Delta, the swanÕs core winter habitat. They sequentially flood 6,000 acres of harvested cropland on Staten Island and attract waterfowl and cranes from mid-September to mid-March, including an estimated 20,000 tundra swans from November through January. In 1995, the Shanks, Ruth Shea, and Dave Paullin proposed to the Fish and Wildlife Service to trap and transport between 50 and 75 trumpeter cygnets and yearlings from the Yellowstone area to the Shanks's ranch, much like what has been done in other states to encourage swans to disperse. Neither the California Department of Fish and Game nor the Pacific Flyway Council rallied around the idea, and while official feet dragged on this proposal, the swans began dispersing enough on their own and didn't need translocating to California. There are drawbacks to attracting swans to farmland. One swan can eat ten pounds of vegetation a day, and swans feeding heavily in newly planted wheat fields can destroy the crop. Their large feet can knead a wet field into a muddy wasteland packed with bathtub-size craters, creating hazardous conditions for farm equipment and their operators. But Sally Shanks claims that such problems have not occurred in California farmlands. Farmers in the Delta routinely flood fields to drown weeds, creating prime habitat for the swans. If anything, she says, swans make a positive contribution: their excrement is a natural fertilizer, and by eating weeds, they reduce or eliminate the need for herbicides later in the year. They pick vegetable fields clean of waste, preventing undesirable opportunist plants, disease, and pest outbreaks. If swans create problems by grazing, they can be discouraged by dogs, loud noises, or obstructions in the fields. Shanks maintains that the real reason she wants to have trumpeter swans on her land is simply because she enjoys them. "The fact is that my husband and I just like them! And so do a lot of other farmers in the Delta," she says. "People in urban areas put a bird feeder out for the same reason." One way or another, with or without government sanction, trumpeters are gradually returning to California. From among the tundra flocks that winter at Staten Island, the Shanks have heard the distinctive trumpeting calls of swans that may have accidentally found their old migration routes, pushed south by the big winter storms in early 1997. With so many species disappearing or hovering towards extinction, it is nice to know that one is making a comeback, in no small part due to the efforts of some determined humans. What could have been a swan song is one of rejoicing--announced with a blast of trumpets. Nora Steiner Mealy is a freelance writer in Davis, California. |
Spring 1998
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