Sandhill Cranes: Our Avian Ambassadors At-Large

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From one of his remote cameras, photographer Joel Sartore captures the cranes taking off from the Platte River. (Joel Sartore/www.joelsartore.com)

By Paul A. Johnsgard and Karine Gil

There are some people, sometimes known 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 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.

Recent research by Karine Gil and Felipe Chavez-Ramirez indicates that the spring population of the central Platte valley has been quite stable recently. The 13-year (to 2009) population peak has averaged 300,000 cranes and has occurred most often during the fourth week of March. Spring arrivals have occurred in three chronologic “waves” over an eight-week period, perhaps in relationship 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 (south of Grand Island) and Wood River, followed sequentially by the stretch from Wood River west to U.S. Highway 10 and east to Highway 34, and lastly in the segment from Shelton west to Overton. The early arrivals in the Grand Island area are probably greaters, from wintering areas in eastern Texas. Later arrivals tend to be from more westerly wintering areas, and the birds average smaller. Roosts of up to 70,000 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 and 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 their 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 among even 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 19th century. Cranes become extraordinarily secretive while breeding, so some of these occasional nestings may go undetected.

Bird-loving Nebraskans often speak proudly of the sandhills as “our sandhill cranes,” although the name “sandhill crane” was not historically derived from their occurrence in the Nebraska Sand Hills. As a result, they tend to underestimate or be unaware of the importance of other regions of the birds’ annual cycle, which stretch at least 4,000 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 20 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 began their journey in Siberia, crossing the Bering Strait in late August and passing over the vast Yukon-Kuskowkwim delta of western Alaska, where they were 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 river 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 moving 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 some 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 30,000 sandhill cranes killed legally each fall in mid-continental 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. For a species that 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 Oct. 8 and continues until late November. During the Audubon Christmas Count of 2006–07, 48,000 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 25,000 sandhill cranes were reported there during the Audubon Christmas Bird Count of 2002–03. By December most sandhill cranes have continued farther south; in the 2008–09 Christmas Count 33,000 sandhill cranes were observed at Muleshoe National Wildlife Refuge in northern Texas, and 95,000 were seen there during the 2007–08 count. In the 2003–04 and 2004–05 counts the largest numbers (21,000 and 17,000) were seen near Elfrida, Ariz. There the cranes gather on small and temporary wetlands such as Whitewater Draw, a state-owned wildlife management area in the Sulfur Springs Valley of southeastern Arizona.

The sandhill cranes of southeastern Arizona, in the Elfrida–Willcox area 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, over 4,000 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 stopped briefly near Kearney and Grand Island. Two went to breeding grounds on the Yukon-Kuskokwim delta, while the other four telemetry-equipped cranes traveled to Siberia’s Chukotka Peninsula and the deltas of the Chaun and Anadyr rivers, arriving in mid- to late May, about the time the tundra becomes snow-free.

For more than 40 years a similar Nebraska celebration of the cranes and other migratory birds has been held in mid-March, primarily through the planning and sponsorship of the Nebraska members of the National Audubon Society. Starting in 1970 at Grand Island as the Spring River Conference, it later moved to Kearney and was renamed the Rivers and Wildlife Celebration. It is now one of the longest-running bird-and-wildlife celebrations in the country. Together in more recent years with Audubon’s Lydia Rowe Sanctuary, the celebration has done much to stimulate spring tourism in the central Platte valley. It has also helped educated people from around the world about sandhill cranes and the other natural attractions of Nebraska’s central Platte Valley.

Other major influences on the conservation of sandhill and whooping cranes in the Platte Valley are The Nature Conservancy and the Crane Trust (until recently called the Platte River Whooping Crane Habitat Maintenance Trust). The trust was established in 1978 as part of an environmental settlement involving the National Wildlife Federation, the State of Nebraska and the Missouri Basin Power Project. The settlement compensated for the ecological damage to the whooping crane’s habitat in the central Platte valley resulting from construction of Grayrocks Dam, then being built on a North Platte River tributary in eastern Wyoming. Since the trust’s establishment, trustees have been from the National Wildlife Federation, the State of Nebraska and the Basin Electric Power Cooperative. Directors over the last 32 years have included J. VanDerwalker, T. Emerton, P. Currier, and F. Chavez-Ramirez. Platte valley habitat acquisition and research on riverine and crane ecology have been major priorities. Its current and new executive director, Charles Cooper, will enlarge the mission of the trust to encompass expanded habitat management and public outreach.

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, have allowed Nebraska to develop and benefit economically from this largest concentration of cranes in the world. It represents one of the world’s greatest wildlife spectacles, easily equal to the great migrations of wildebeests on Tanzania’s Serengeti or the caribou in arctic Canada and Alaska. And for Nebraskans, it is no more than a day’s drive away!

Sunset with the cranes. (Paul A. Johnsgard)

 

References

Bzdek, Maren T. “In the Last 30 years, the Platte River Trust Has Changed the Way We View the River.” Prairie Fire (June 2008).

Gil, Karine and Felipe Chavez-Ramirez. “Temporal-spacial Abundance of Roosting Sandhill Cranes in the Central Platte Valley, Nebraska, USA.” Unpublished manuscript.

Gil, Karine and Paul A. Johnsgard. “The Whooping Cranes, Survivors against All Odds.” Prairie Fire (September 2010).

Johnsgard, Paul A. “The Wings of March.” Prairie Fire (March 2010).

 

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