NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.
Issue link: http://mag.outdoornebraska.gov/i/1087556
30 Nebraskaland • March 2019 food in the form of invertebrates. The cranes' use of the river was likely disrupted by unregulated spring hunting until the practice was banned by the Migratory Bird Treaty Act in 1918. It changed again when settlement brought farming to the Platte River Valley, and corn that didn't make it into the combine gave cranes a high- energy food source that let them fatten up for the remainder of their journey. Irrigation brought more corn, but it also changed the river. Farmers began digging ditches to carry water to their crops in the late 1800s. Large dams in the basin followed, the fi rst being Pathfi nder Dam on the North Platte in Wyoming in 1908 and the last and largest the Tri-County Project, which began operating in 1938 and included Kingsley Dam, completed in 1941, and Lake McConaughy near Ogallala. With each new dam and diversion for irrigation or hydroelectric power, the river dropped, allowing vegetation to sprout on the exposed, moist ground. With high spring fl ows trapped in upstream reservoirs, there was nothing to scour the river clean. Eventually, what once was riverbed became woodland composed primarily of cottonwoods at fi rst, and later by Russian olive and eastern redcedar, and the remaining fl ows were restricted to narrower, deeper, and more winding channels. Described by one journalist in the 1880s as "a mile wide and an inch deep," the Platte was actually wider in places. Yet by the 1950s, it spanned only 50 yards between North Platte, where most of the water was diverted by the Tri-County project, and Overton, where some of that water is returned. The succession was not good for cranes, which soon abandoned the river above Overton. As accretion and woodland growth continued to move eastward, so did the cranes. A 1957 study found that 60 percent of the cranes stopping on the Platte in the spring were found between Overton and Kearney. By the late 1970s, most were between Kearney and Grand Island. The Shift Continues Population estimates of cranes, while an inexact science, have been conducted since the 1950s by various entities, including the U.S. Fish and Wildlife Service, which does an intensive air and ground survey of the valley in late March each year. Since 1998, with the exception of two years, the Crane Trust has from mid-February to mid-April conducted weekly survey fl ights on the river between Overton and Chapman. The methods used and routes fl own have been mostly the same since 2002: From a fi xed wing aircraft, observers estimate the number of birds on the river and the adjacent fi elds and take photographs of selected roosts. Back on the ground, they analyze the photographs and adjust their estimates as needed. Their highest recorded count of 598,000 came on March 22, 2018, a fi gure that does not account for cranes that left the river for fi elds farther from the river than observers could count. The service's count, which reaches farther from the river and continues west through the North Platte River Valley, estimated there were a record 1 million cranes on the rivers during the same week last March. The Crane Trust's survey data has Aerial photos show the stark difference in habitat in two reaches of the central Platte River. Near Odessa (top), nearly all of the forested area pictured was river channel a century ago. At The Crane Trust's headquarters south of Alda (bottom), the river looks like much like it did a century ago, with both channels retaining their width, little woodland encroachment and much of the surrounding landscape in meadow. While the width of the river channel is similar in these reaches today, the change in character has caused sandhill cranes to abandon the area near Odessa.