A Congruence of Cranes
with Karine Gil-Weir
There are some people, sometimes referred to as craniacs, whose calendars recognize only two seasons: crane season and the rest of the year. In Nebraska the prime season for observing sandhill cranes occupies only about eight short weeks in spring, from mid-February (or whenever the Platte River fully thaws) to about mid-April. The usual peak crane populations occur during late March but rarely may be as late as early April. Sandhill crane numbers quickly trail off during the first warm days and with the south winds of April, when migratory conditions become optimum. Then the birds often depart almost en masse, leaving the state about the same time that the first whooping cranes are arriving from their localized wintering area (Aransas National Wildlife Refuge) in coastal Texas.
Research by Dr. Karine Gil-Weir indicates that the spring crane population of the central Platte Valley has been increasing very slowly during the past decade. The population peak during 2010 reached 479,000 sandhill cranes; however, from 1998 to 2010 the average was approximately 300,000 cranes, and the peak occurred most often during the fourth week of March. Spring arrivals have occurred in three chronologic “waves” over an eight-week period, perhaps in relation to the birds’ relative breeding status or to the relative desirability of the various roosting sites. The earliest average arrivals and departures occurred in river stretches between U.S. Highway 281 (directly south of Grand Island) and Wood River, followed sequentially by the stretch from Wood River west to U.S. Highways 34 and 10 and by the segment from Shelton west to Odessa. Roosts of up to seventy-two thousand birds were found; larger roosts were associated with long-term river management activities such as roost and channel rehabilitation. Departures occurred six to eight weeks after the river segments were initially occupied.
The sandhill cranes are present in Nebraska for an even shorter period during fall, mostly from late September to early November, peaking in early October. Relatively few Nebraskans see them then, as they tend to overfly the state, frequently passing directly from fall staging areas in western North Dakota and adjacent Canada south to temporary migratory stopover sites south of Nebraska. The most important of these southern migratory stopover sites are a few wildlife refuges in Kansas (especially Quivira National Wildlife Refuge) and Oklahoma (primarily Salt Plains National Wildlife Refuge), which are only a few hundred miles from the cranes’ final winter destinations in Arizona, New Mexico, Texas, and northern Mexico. Their major Nebraska spring staging area, the Platte River Valley, is liberally sprinkled throughout the fall with trigger-happy waterfowl hunters, so that stopping there during autumn is a recipe for potential death, even among federally protected species such as cranes.
It is true that in recent years a very few sandhill cranes have remained in Nebraska throughout spring and summer, and some have even successfully bred here. These nestings have most often occurred on rather remote wetlands such as those of the Rainwater Basin and the Nebraska Sandhills, the latter having been part of their historic Great Plains nesting range during the nineteenth century. Cranes become extraordinarily secretive while breeding, so some of these occasional nestings may go undetected.
Bird-loving Nebraskans often speak proudly of the sandhill cranes as “our sandhill cranes,” although the name “sandhill crane” was not historically derived from their occurrence in the Nebraska Sandhills. As a result, Nebraskans tend to underestimate or be unaware of the importance of other regions in the birds’ annual cycle, which stretches at least four thousand miles over two continents, from northeastern Siberia, across Alaska and Canada, and south to northern Mexico. The birds are able to survive the rigors of breeding in arctic tundra, where freezing temperatures and blizzard-like conditions may occur at any time over the brief summer months. There predators such as golden eagles pose potential threats to adults, and arctic foxes, gulls, and jaegers are on constant alert for untended eggs or chicks. From late fall through winter the cranes must contrastingly adapt to semidesert or even desert conditions, where water and food supplies are limited and where at least one out of twenty is likely to be killed by hunters in the name of sport.
Between these two extremes, the cranes must traverse a distance up to almost twice as far as that from San Francisco to New York. Twice yearly they must travel over largely trackless lands of tundra, boreal forests, and grasslands, skirting the edges of North America’s highest mountain ranges and visually navigating by the simple collective memories of the flock. Any single human able to complete this achievement in the face of all these collective dangers would be awarded a medal for personal fortitude and heroism. What the cranes receive instead is a barrage of gunfire over almost their entire route.
Many of the lesser sandhill cranes that migrate each fall through Nebraska begin their journey in Siberia, crossing the Bering Strait in late August and passing over the vast Yukon-Kuskowkwim delta of western Alaska, where they are joined by the local breeders, possibly in similar numbers. These birds move northeast along the Yukon Valley until they reach its confluence with the Tanana River, when they turn east and follow the Tanana southeast to a staging area upstream near Delta Junction. A few thousand of them stop for a few weeks at the edge of Fairbanks to rest and forage at Creamer’s Field Migratory Waterfowl Refuge, where their arrival is eagerly awaited and celebrated with the annual Tanana Valley Sandhill Crane Festival. By early September tens of thousands of sandhill cranes move east along the Alaska Range and pass in front of the majestic north face of Mt. McKinley, North America’s highest mountain. Except for the cranes breeding south of the Alaska Range, which migrate along the Pacific coast and winter in California, all of Alaska’s sandhills then continue to fly southeastwardly. After leaving Alaska they follow the upper tributaries of the Yukon River between the Pelly and Selwyn Mountain ranges and continue southeast over Canada’s boreal forest and onward into the northern Great Plains of Alberta and Saskatchewan. There, in spite of heavy local hunting, they can rest and forage for several weeks in grain fields, readying themselves for the long and dangerous trip over the central Great Plains, where they will face crane hunters in every state that they pass though except Nebraska.
Of all the nearly thirty thousand sandhill cranes killed legally each fall in midcontinental North America, the largest number are shot in Texas, followed closely by North Dakota. These killings destroy lifelong pair bonds and disrupt family bonds, probably making the young more vulnerable to hunting-related mortality. Given that the species does virtually no economic damage to humans and is regarded in many cultures as a symbol of peace, longevity, and fidelity, killing cranes seems better described as a sacrilege than as a sport.
By November large numbers of sandhill cranes have reached the southern Great Plains in Kansas. The main fall migration begins about October 8 and continues until late November. During the Audubon Christmas Bird Count of 2006–7, forty-eight thousand sandhill cranes were counted at Quivira National Wildlife Refuge, a national high-count record for that year. In Oklahoma the largest numbers gather at Salt Plains National Wildlife Refuge; about twenty-five thousand sandhill cranes were reported there during the Audubon Christmas Count of 2002–3. By December most sandhill cranes have continued farther south; in the 2008–9 Christmas Count thirty-three thousand sandhill cranes were observed at Muleshoe National Wildlife Refuge in northern Texas, and ninety-five thousand were seen there during the 2007–8 count. In the 2003–4 and 2004–5 counts the largest numbers (twenty-one thousand and seventeen thousand) were seen in southeastern Arizona, the westernmost wintering area used by the midcontinental population of lesser sandhill cranes.
The sandhill cranes wintering in southeastern Arizona are of special interest, as they are the southwesternmost wintering cranes that pass though Nebraska, staging each March in the North Platte Valley. They also are on average the smallest of the lesser sandhill cranes and probably migrate the farthest, as they nest in northeastern Siberia, roughly four thousand miles away. Six telemetry-equipped sandhills that wintered in New Mexico and Arizona left their wintering grounds in early to mid-March. Two of them went to breeding grounds on the Yukon-Kuskokwim delta, while the other four telemetry-equipped cranes traveled to Siberia’s Chukotka Peninsula, arriving in mid- to late May, about the time the tundra becomes snow-free. Lesser sandhills are now known to breed as far west in Siberia as the Lena River delta.
For more than forty years a celebration of the cranes and other migratory birds has been held during mid-March in Nebraska, primarily through the planning and sponsorship of the Nebraska members of the National Audubon Society. Starting in 1970 and now known as the Audubon’s Nebraska Crane Festival, it is one of the longest-running bird and wildlife celebrations in the country. Together in more recent years with the Rowe Sanctuary and Ian Nicolson Audubon Center near Gibbon, the celebration has done much to stimulate spring tourism in the central Platte Valley. It has also helped educate people from around the world about sandhill cranes and the other natural attractions of Nebraska’s central Platte Valley.
As described in chapter 2, a thirteen-year Platte River Recovery Implementation Program began in 2006, jointly supported by agreements among the federal government, Colorado, Wyoming, and Nebraska. It is providing over $100 million for wetland purchase and restoration in the central Platte Valley to improve habitats for whooping cranes and three other nationally endangered and threatened species. Other major influences on the conservation of sandhill and whooping cranes and their habitats in the Platte Valley are several nonprofit conservation groups, such as the National Audubon Society, the National Wildlife Federation, the Nature Conservancy, and the Crane Trust.
Established in 1978, the Crane Trust (known as the Platte River Whooping Crane Habitat Maintenance Trust until 2012) was formed as part of an environmental settlement among the National Wildlife Federation, the State of Nebraska, and the Missouri Basin Power Project involving the downstream ecological effects of a dam being constructed on a North Platte River tributary in Wyoming. It has since played an important role in population monitoring and habitat restoration in the central Platte Valley, and in the past few years it has expanded its educational outreach by incorporating the Crane Trust Visitor Center at I-80 exit 305 into its purview. The Rowe Sanctuary and Ian Nicolson Audubon Center and the Crane Trust Visitor Center offer birders a wide choice of crane-viewing opportunities, ranging from single-person overnight blinds for professional photographers, situated only a few dozen yards from crane roosts, to blinds accommodating up to about thirty persons, ideal for groups and the general public.
Collectively, cooperation among state, federal, and many nonprofit conservation groups, as well as contemporary farming practices and strict control of the Platte’s vital water resources, has allowed Nebraska to develop economically beneficial ecotourism from this largest concentration of cranes in the world. It represents one of the world’s greatest migratory spectacles, easily equal to the great migrations of wildebeests across East Africa’s Serengeti and Masai Mara plains or the caribou herd movements in arctic Canada and Alaska as they plod to and from their calving grounds. And, at least for Nebraskans, the spectacle is no more than a few hundred miles away!