Nature Blog Network

Tuesday, March 15, 2011

Best books - Sandhill Cranes in the Great Plains and elsewhere

Sandhill and Whooping Cranes: Ancient Voices over America's Wetlands by Paul A. Johnsgard. Bison Books of the University of Nebraska Press [published 2011] and

On Ancient Wings: the Sandhill Cranes of North America by Michael Forsberg [published 2004]

The spring staging of Sandhill Cranes in the shallows of the Platte River in Nebraska ranks among the great mass migratory events on the globe.

Paul Johnsgard provides an overview of the status for Sandhill and Whooping Cranes that updates his classic Crane Music [1991].
The prose is consistently graceful and the illustrations both meticulously accurate and artistically delightful. The first three chapters of this book are status reports on "Lesser Sandhills", "The Other Sandhills", and "Whooping Cranes". Each blends history and biology, spiced with personal observations. Paul imbues the descriptions with awe and respect for these magnificent birds.

Lesser Sandhill Cranes endured the depredations of 19th century market and sport hunting and now the Platte collects 400,000 to 500,000 birds every March. Nonetheless, these cranes are still under some threat, from hunting pressure during the winter in Texas, from atrophy of the Platte due to agricultural irrigation, and from competition for food from thousands of resident Canada Geese and millions of migratory Snow Geese that arrive in Nebraska a few weeks earlier.

The mid-continent crane populations have a hourglass-shaped migration pattern. In late February and March, they converge on the Platte from wintering sites spread from western New Mexico and northern Mexico to the Gulf Coast of Texas. Once in the spring fueling mode in Nebraska, the cranes spend weeks of day-times converting waste corn from the surrounding fields into fat to store for the second major leg of their migration. Every night, they return to dodge the powerlines and touch down in cacophonous cascades until they can roost, huddled in swirling transient clusters in the shallows of the river.

On a warm March day with rising thermals, groups of birds spiral gently upward and splay out to the north, finally ending their journeys at higher latitudes from Hudson Bay to Siberia.  As they near their traditional nesting territories, ponds and marshes are still icy. Within 3-4 months, the crane colts are fledged and as temperatures dip below freezing again and families start a long more leisurely journey south.

The Other Sandhills are a collection of populations or races that are rather like clans of nomadic people.  The birds differ somewhat in size (weight, wing-spread, bill-length, etc.) but are mostly distinguished by migration geography.  Some (technically Lessers) migrate from nesting grounds in southwest Alaska to California, others (technically Greaters) from Idaho to New Mexico or (the Great Lakes population) from Michigan to Florida.  These migratory patterns probably reflect the distinct cultures of each population that are passed year-by-year from experienced birds to younger ones as they travel together.

Some Other Sandhill populations (subspecies?) are non-migratory. The resident cranes in Florida grasslands, suburbs, and shopping centers overlap with migrants from Michigan in winter months. The more remote groups in Mississippi and Cuba remain threatened and isolated. A tiny population of these long-lived birds has persisted for many decades on a National Wildlife Refuge in Mississippi, often with yearly infusions of new colts hatched in captivity.

The stature and majesty of Whooping Cranes and their plumage captivates almost everyone who sees them. During the early years of the 20th century, pressure from the millinery markets of sophisticates decimated their populations. In 1937, the establishment of the Port Aransas National Wildlife Refuge on the Gulf coast of Texas preserved a dedicated wintering ground, albeit precariously close to heavy commercial barge traffic on an intercoastal waterway.  Occasional illegal harvesting persisted, but somehow numbers held steady at a few dozen adults until the remote nesting ground for the Port Aransas flock was discovered in Canada twenty years later. Conservation efforts in Texas and Alberta and appeals to reduce hunting have paid off such that 263 cranes started from Texas on their journey toward Canada in 2010, along the path depicted in Johnsgard's map to the left. Continued vigilance and monitoring of the individual birds each year must remain a high priority.

Many well-publicized efforts have been devoted to establishing other Whooping Crane populations.  These include a failed attempt to cross-foster Whoopers with Sandhill parents in Idaho that started well but faltered, and a multi-year struggle, that was ultimately abandoned, to create a resident population in Florida.  As of 2009, the 22 surviving Whooping Cranes from this flock are being protected and monitored.

Still ongoing is Operation Migration, an entrancing project of a non-profit corporation working with the International Crane Foundation and the USGS in Patuxent (MD). Operation Migration nurtures hatchlings chicks at the ICF in Wisconsin and then teaches the young colts to migrate in the fall by following an ultralight airplane to Florida and returning in the spring, led by the ultralight back to Wisconsin. This flashy project seems to be working as some of the the returning Whooping Cranes are making nests in Wisconsin. The next critical landmarks are sustained nesting in the wild, fledging of significant numbers of colts, and independent migration (without an ultralight leader) to Florida.

Very recently, there is a new attempt to establish another resident population, this time in Louisiana. It will be many decades before we will know if any of these investments yield self-sustaining populations.

Like Sandhills, Texas Whooping Cranes migrate through Kansas, Nebraska, and the Dakotas, but they travel in small groups in the late spring.  Cranes are particularly vulnerable during these long migrations. The impacts of changing fashions in agricultural economics, pressure for increased biofuel production, and drought cycles which may be exacerbated by global climate change, are some of the factors that menace crane stopover sites, of which the most important is the Platte River valley.

The Appendix of Johnsgard's s slim, information-packed volume tells the reader exactly when and where to find cranes in 34 states and provinces of the US and Canada. It is very helpful to have one list of these unheralded habitats where cranes can be observed by carefully scheduling a visit.

Mike Forsberg may be best-known for his stunning images of fauna, flora, and scenery of the Great Plains. He is a keen observer and careful student of natural history, an avid conservationist, and a lucid writer. On Ancient Wings grew from several years of watching and photographing different populations of cranes.

On Ancient Wings is a series of vignettes of cranes in the wild, as Mike traveled from Alaska to Mexico, across to Florida and down to Cuba.

The informative text is enhanced by Mike's striking photographs of the cranes, their behavior, the neighboring animals and plants, and the landscapes. The images almost overpower the narrative that likewise deserves very careful study.  Mike introduces the reader to the local culture and the people who study and protect the cranes. Each crane population is unique and Mike's journal entries provide great local flavor.

Although Mike Forsberg started as a still photographer, more recently he has become skilled with video as well. His talent was showcased a few years ago in a NET (Nebraska Educational Television) video production for On Ancient Wings. 

For a lyrical introduction to Mike's skills, view the recent Flash video promoting his upcoming NET production on the Great Plains - America's lingering wild  or visit his exhibition in April 2011 at the National Museum of Wildlife Art in Great Falls, Montana.

Great Plains promo - NET Nebraska and Michael Forsberg from Michael FORSBERG on Vimeo.

Johnsgard's Sandhill and Whooping Cranes and Forsberg's On Ancient Wings very nicely complement one another. Both have a mix of the big picture and specificity, and each offers an informed original perspective on cranes and their biologies. Royalties from these books go to the Rowe Audubon Sanctuary, a craniac's mecca a few miles east of Kearney, Nebraska.