A Feathered River Across the Sky

by Joel Greenberg

Organisms evolve in specific ecosystems. Over millennia they adapt so as to most effectively deal with the physical conditions of their range and to coexist with the other life-forms with which they share space and compete for resources. They develop physical attributes and behaviors that allow them to procure food or avoid predators. Long-term exposure to pathogens means that surviving hosts build resistance. But when a stranger appears, new to the evolutionary history of the established fauna and flora, calamity often results.

  Niagara Falls prevents Atlantic fish from ascending the Great Lakes any farther than the western end of Lake Ontario. The construction of canals, however, has allowed sea lampreys and alewives to circumvent the forbidding barrier and colonize the upper lakes, leaving biological desolation in their wake. Sea lampreys use their jawless mouths armed with tiny, sharp teeth to attach themselves to larger fish, whose bodily fluids provide sustenance to the new passengers. When the host is a saltwater species weighing hundreds of pounds, little harm ensues, but when the victim is a twenty-pound lake trout, the chances of its survival plummet. Alewives, on the other hand, feed on plankton, but reached such numbers they outcompeted the native planktors. Lake Michigan provides a stark example of how these two oceanic fish devastated the existing ecosystem. Burbot, a type of cod, and lake trout, for forty years the most valuable fishery in the lake, swam atop the deepwater food chain, preying on seven species of ciscoes or chubs that foraged on plankton. Already reduced by overfishing, the trout and all but one of the ciscoes proved highly vulnerable to the invaders and perished from the lake within five decades of the lamprey arrival. Four of the ciscoes no longer exist anywhere on the planet.27

  The brown tree snake is native to Australasia. When it arrived in Guam as a stowaway, it wiped out the bird life of its new home, driving at least one species to extinction and another to virtual extinction. But nowhere has avian diversity suffered more than in the Hawaiian archipelago, which holds the distinction of having lost more of its native birds due to anthropogenic causes than any other place in the world: seventy-one endemic species have vanished since human beings first arrived. Much of this destruction was caused by mosquitoes, which were not present on Hawaii until their inadvertent introduction in 1826. These bloodsucking insects carry and spread avian malaria and avian pox virus, two deadly diseases also previously unknown to the local birds. Currently almost no native land birds are found at elevations lower than four thousand feet, the highest altitude mosquitoes can tolerate.28

  North American birds took a big hit with the introduction of West Nile virus, a recent arrival from Africa and Eurasia that also infects birds through the feeding habits of mosquitoes. As the disease swept across the continent and then south into Mexico and South America, the newly affected landscapes supported many fewer crows, jays, magpies, hawks, and sage grouse than before. The yellow-billed magpie is restricted to portions of California, and in two years the virus reduced the entire population by almost half. But populations are recovering as the avian survivors develop immunity.29

  Another disease currently running rampant through eastern North American is ravaging bat populations. White-nose syndrome, caused by the fungus Geomyces destructans, was first noted in a New York cave in 2006. Since then, close to 6 million bats of nine species have died. Three of the affected species—Indiana myotis, gray myotis, and Virginia big-eared bats—were already federally endangered. Professor Thomas Kunz of Boston University likened the magnitude of this population decline to the major subject of this book: “I think you have to go back to the 1800s, to the loss of the passenger pigeon, to find something similar.”30

  The syndrome irritates the skin, which causes bats to awake more frequently during hibernation. This additional activity depletes energy reserves they need to survive the winter. In some places, mortality rates of infested bats have reached 100 percent. Most likely, the fungus is a European native that was introduced to North American caves by human visitors. But it is also possible, however, that the fungus has always been native to these shores but has only recently mutated into the form that is causing so much harm.31

  More adorable than any fungus, cats (Felis catus), either feral or those whose irresponsible owners allow them to roam outdoors, are no slouches in their depredations on native wildlife. These felines likely take in excess of 530 million birds a year in the United States. Small mammals, reptiles, and amphibians are on the menu as well. (And even those kitties subjected to clawectomies continue to be effective predators.) Birds restricted to islands have proven to be the most vulnerable, as cats have contributed to the extinction of thirty-three such species.32

  Why should we care about extinction? In their classic 1981 book, Extinction: The Causes and Consequences of the Disappearance of Species, Paul and Anne Ehrlich list the four major categories of reasons why species should be preserved: (1) other life-forms have a right to exist, and ethical decisions should not be based solely on human benefits; (2) other species are aesthetically pleasing and add to human felicity by their beauty and character; (3) other species provide economic, medical, and other “direct benefits” by their continued existence; and (4) extinctions have indirect and long-term effects on ecosystems of which humans are also a part; the Ehrlichs illustrate this point with the analogy that the “popping of rivets” of an aircraft would eventually render the plane unable to fly. For sixty-five pages they elaborate on these reasons. I believe that all of these arguments are convincing, although valuing biodiversity is no longer an intellectual point for me. I take it as a given, a truth as primary as the Golden Rule or the efficacy of science.

  Brian Anderson, director of the Illinois Natural History Survey, suggests that extinction be considered in personal terms. There is nothing esoteric or technical in this. Think of the excitement manifested on a child’s face when the fishing pole she is holding begins reverberating with the power of a trout at the end of the line. The chorister hidden in the canopy of the neighbor’s oak penetrates your consciousness and makes you wonder. Perhaps you savor the sights and scents of a late-April hike through the woods of a nearby park when the loam is blanketed with spring beauties, trillium, and Virginia bluebells. A full-antlered bull elk bugling against the shimmering gold of autumn aspen might forever be etched in your memory as a stunning tableau, or it might be inspiration for the coming bow season. And many are the gustatory pleasures associated with cod, lobster, and other morsels of the sea. How much poorer and less enjoyable would life be if these and other creatures vanished? But, of course, that is impossible.33

  Acknowledgments

  I started my research on this book in the fall of 2009. Besides combing the literature with the help of several librarians, I solicited information on Publore and other specialist listservs including the birding listservs of close to twenty states. This netted a host of valuable materials and, more important perhaps, contacts with interested people who have proved to be strong allies throughout this ongoing effort. I spent nine days in Madison, Wisconsin, going through the boxes of Schorger’s personal papers in the University of Wisconsin’s Archives and the binders filled with his passenger pigeon notes that are kept at the Department of Forest and Wildlife Ecology. There were also trips to numerous other places through former passenger pigeon range. Throughout this I was aided by a host of people, a number of whom have become good friends. The following is a partial list of those who provided information, reviewed chapters, provided lodging, or provided other assistance that made completion of this book possible (some names appear in the text):

  Bob Adams, Glenn Adelson, David Aftandilian, Renee and David Baade, Paul Baicich, Kyle Bagnall, Mark Barrow, Eleanor Bartell, Fred Baumgarten, Craig Benkman, David Blockstein, Charlie Bombaci, Ken Brock, Simon Bronner, Neely Bruce, Alan Bruner, Michael Bryson, Blair Campbell, Angelo Capparella, Stan Casto, Elisabeth Condon, Bill Cook, Mary Cummings, Bob Currin, Stan De Orsey, Julia Di Liberti, Jim Ducey, Tim Earle, Josh Engel, Nancy Faller, Ralph Finch, Raymond Fogelson, Beryl Gabel, Paul Gardner, Nancy Gif
t, Nancy Glick, Bob Glotzhober, Ben Goluboff, Stephen Gordon, Don Gorney, Terri Gorney, Michel Gosselin, Robin and Travis Greenberg, Nadia Gronkowski, Greg Hanson, Stan Hedeen, Lynn Hepler, Destry Hoffard, David Horn, Richard Horwitz, Mary Hufford, Connie Ingham, Julia Innes, Paul James, Carolyn Jaskula, Jeanette Jaskula, Kevin Johnson, Jacqueline Johnson, Kenn and Kim Kaufman, Tom Kastle, John Kay, Rudolf Keller, Tom Kent, Cynthia Sue Kerchmar, Alan Keyser, Kindler family, Gretchen Knapp (reviewed entire manuscript), Deborah Lahey, Garrie (reviewed entire manuscript) and Lynn Landry, Cindy Laug, Ellen Lawlor, Leo Lefevre, Bob Levin, John Leonard, Wendy Lilly, Karen Lippy, John Low, Damon Lowe, Peter Ludwig, Dan Marsh, Terrance Martin, Bob Maul, Carol McCardell, Todd McGrain, Curt Meine, Ed Meyer, Janet Millenson, Steve Mirick, David Mrazek, Greg Nobles, Ben Novak, Mark Peck, Justin Peter, Wayne Peterson, Pamela Rasmussen, Steve Rogers, Kayo Roy, Sarah Rupert, Robert Russell, John Ruthven, Rita Rutledge, Sara and Steve Sass, Linda Scarth, Jonathon Schlesinger, Jennifer Schmidt, Theresia Schwinghammer, David Scofield, Geoffrey Sea, Skip Shand, Jerri Sierocki, Andy Sigler, Mathew Sivils, Arthur Smith, Michael Solomon, Kathleen Soler, David Stanley, Tom Steel, Nancy Steiber, Wendy Strothman, Steve Sullivan, Jeff Sundberg, Stephanie Szakal, Stan Temple, Jeremiah Trimble, Sophia Twichell, Tim Wallace, Jason Weckstein, Susan Wegner, Daniel Weinman, Bill Whan (reviewed entire manuscript), Phil Willink, Jon Wuepper, Owen Youngman, and Kristof Zyskowski.

  A few of the names on this list have appeared in the acknowledgments of my other books as well. I cannot express the full level of my appreciation for these long-term friends whose love and other support have helped make all of this possible.

  Appendix: A Passenger Pigeon Miscellany

  I. CONSERVATION MEASURES: WAY TOO LITTLE, WAY TOO LATE

  Within four centuries of North American civilization (or modified barbarism) we can be credited with the wiping into the past of at least three species of animal life originally so phenomenally abundant and so strikingly characteristic in themselves as to evoke the wonders and amazement of the entire world.

  —GEORGE ATKINSON, “A REVIEW-HISTORY OF THE

  PASSENGER PIGEON IN MANITOBA,” 1905

  John Josselyn visited New England twice, the second time staying from 1663 to 1671. After describing the abundance of passenger pigeons (quoted in chapter 3), he is the first author who notes a decline in the bird’s population: “But of late they are much diminished, the English taking them with Nets.” A few other seventeenth-and eighteenth-century authors, including Kalm and Mather, collected similar sentiments. Kalm’s informants thought the pigeon decline was due to a growing human population, the felling of timber, and increasing competition with swine for mast. These passages are significant not because they reflect an actual depletion in pigeon numbers on a range-wide scale, but because they are the first statements suggesting the possibility that the species could be vulnerable as a consequence of human behavior.

  John Audubon seems to be the first to address the impacts that mass slaughter might have on the species’ long-term prospects, and for that he deserves accolades even if he got it wrong. After describing the carnage at one huge roost, he tackles the obvious question: “Persons unacquainted with these birds might naturally conclude that such dreadful havoc would soon put an end to the species. But I have satisfied myself, by long observation, that nothing but the gradual diminution of our forests can accomplish their decrease, as they not infrequently quadruple their numbers yearly, and always at least double it.” But in reaching this conclusion, he presumed incorrectly that the birds lay two eggs per nest and that they regularly nest multiple times a year.

  As is so often the case, it took a foreigner to glimpse the truth. The de Tocqueville of passenger pigeons was the French writer Benedict Henry Revoil, who traveled through the United States in the 1840s. After having witnessed butchery at a pigeon roost at Hartford, Kentucky, in the fall of 1847, he demonstrated singular perspicacity in his astonishing prediction: “Everything leads to the belief that the pigeons, which cannot endure isolation and are forced to flee or to change their manners of living according to the rate in which the territory of North America will be populated more and more by the European inflow, will simply end by disappearing from this continent, and, if the world does not end this before a century, I will wager with the first hunter coming that the amateur of ornithology will find no more wild pigeons, except those in the Museums of Natural History.” Events would show him to have been overly optimistic by about fifty years.

  As the decades of the nineteenth century reached their final two or three, the occasional public statement would be made admonishing those engaged in the killing. The Mauston (Wisconsin) Star printed this dispatch from its New Lisbon correspondent in May 25, 1882: “Some of our prominent businessmen are busily engaged … in destroying thousands of poor little helpless young pigeons not yet with feathers, and encouraging others in the wholesale murder, and all from a greedy desire to catch a few squabs to ship and sell for thirty cents per dozen. Money! Fie upon you for shame.” The American Field published a plea on behalf of the species the very next month: “But this fact is patent and admits of no argument to the contrary: that unless the trapping and shooting of the wild pigeon is stopped during the period the birds are nesting, extermination must necessarily follow, and rapidly.” To protect one nesting in Wisconsin, a petition was drawn up and signed by various citizens requesting that the governor send out the state militia to prevent further hunting. J. B. Oviatt, the Pennsylvania pigeoner, said of his fellow netters, “If they knew that the pigeon were decreasing, they didn’t want it known. For years I said the pigeons were decreasing, and they [most netters] were afraid a law would be passed, which there should have been” (Scherer 42).

  In fact, laws relating to passenger pigeons were on the books, many of which stayed in effect long after the birds were gone. In 1848, Massachusetts became the first state to enact legislation dealing specifically with passenger pigeons. Rising up to quell a grave injustice, the legislature passed a law to protect netters. Should any miscreant impede the activities of this class of worker by firing guns or otherwise scaring off pigeons, he would be subject to a fine, damages, or punishment as a trespasser.

  Vermont’s statute three years later actually aimed to provide some protection to the bird, albeit not much. The pigeon was considered a nongame species, and thus the citizenry was prohibited from destroying eggs or nests. A violation could bring a fine of a dollar, but apparently the law was rarely enforced (Young 248).

  The Ohio Senate looked at the need to protect passenger pigeons and issued findings that are widely quoted in the passenger pigeon literature. The 1857 report is ranked by the Ohio Historical Society as the fifth most embarrassing moment in the state’s history, behind such events as the burning of the Cuyahoga River and the discovery in 1953 that Congress had never formally adopted a resolution admitting the state to the union. The legislative committee wrote, “The passenger pigeon needs no protection. Wonderfully prolific, having the vast forests of the North as its breeding grounds, travelling hundreds of miles in search of food, it is here to-day, and elsewhere tomorrow, and no ordinary destruction can lessen them or be missed from the myriads that are yearly produced.”

  Canada’s restrictions on the exploitation of passenger pigeons lagged behind those of the states. Under its Small Bird Act of 1887, Ontario specifically excluded the pigeon as being among the birds that could no longer “be at any time killed or molested.” A revision of the statute ten years later seems to have finally granted the protection that might have helped if there had been any birds left to protect. Game laws enacted in Quebec in 1899 and Manitoba in 1891 failed to provide the species any relief. The bird’s extinction saved lawmakers the trouble of having to pass any protective measures (Mitchell 147).

  Most of the laws that were eventually put in place in the United States modeled themselves after the one passed in New York in 1861. No disturbances were allowed at the actual nesting sites, and there coul
d be no gunfire within a mile. The distances varied between states. Pennsylvania would also require that out-of-state pigeoners buy a county license for $50 to ply their trade, but apparently no one was ever prosecuted under the law. Massachusetts in 1888 did pass a potentially effective law when it banned pigeon hunting from May to October, when what few pigeons still existed were most likely to be in the state.

  Michigan was the only jurisdiction to eventually ban all killing of passenger pigeons. As mentioned earlier, this occurred in 1897, just a year before the last pigeons were to be recorded from the state. But Michigan’s first law affecting pigeons was in 1869. Under this statute, they were considered neither songbirds nor game birds and warranted their own separate section. A distinction was made between places where the birds nested and where they roosted. At nesting places, it was illegal to shoot pigeons within one half mile, but at roosts the shooting ban applied only to the actual site. Nothing restricted where or when netting could occur. Six years later the law was amended to provide a tiny bit more protection: the distance from a nesting where one could now lawfully shoot pigeons was extended to a mile. There was also a purported limitation on netting that read, “No person … shall, with trap, snare, or net, or other manner, take or attempt to take, or kill or destroy, or attempt to destroy, any wild pigeon, at or within two miles of such nesting place at any time from the beginning of the nesting until after the last hatching of such nesting.” Note the final eight words: once the last eggs hatched, market hunters could have free rein. Protection adhered to the netters rather than the pigeons. And so the law stood until its revision in 1897, when for the first and only time in U.S. history a state granted passenger pigeons complete protection. That the provision called for the reinstatement of regulated hunting for the species in 1907 was really moot even at the time of its enactment. (Full citations are in the bibliography.)