Nebraskaland March 2019

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.

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Page 34 of 59

March 2019 • Nebraskaland 35 Canada, arrives later and fi lls in western portions of the region. The Crane Trust's survey data, because it spans the entire timeframe in which the cranes are on the Platte, paints a clearer picture of this staggered arrival, with counts in eastern segments peaking about two weeks ahead of the west. It also shows how the overall peak, which can be infl uenced by weather, varies from year to year. The data also showed that cranes have been arriving, on average, a little more than a day earlier each year since 2002. A century ago, the fi rst reports of cranes arriving on the Platte came in late March. Now they come in early February, and a few cranes have even wintered here in recent years. The study looked at weather in wintering areas on the Texas coast and elsewhere and found it was a fairly reliable predictor in their arrival date. "What's interesting is a 1 degree average increase in average temperature in Texas in January and February basically meant 20,000 more birds came to Nebraska in week 5 (mid- March) of the surveys," Caven said. The advancing migration date is not exclusive to sandhill cranes. Other studies have found that whooping cranes in North America and common cranes in France are also migrating earlier, trends Caven said could be a result of climate change or a combination of many factors, including the availability of waste grain or drought. "That doesn't mean that they're leaving early though," Caven said. "They're coming 20 days earlier but they're staying a little bit longer. So the peak hasn't changed as much as the arrival date." What Now? Researchers watching the transformation of the Platte as irrigation expanded recognized the importance of a wide-open river to cranes and other wildlife. Since the early 1980s, the Crane Trust, as well as numerous other organizations, including the Nebraska Game and Parks Commission, The Nature Conservancy, Audubon Society and, more recently, the Platte River Recovery and Implementation Program, have been working to restore and maintain the river's historic character in the central Platte Valley. The groups have cleared riparian woodlands, restored grasslands and wet meadows and, when the river is low, disked the channel to inhibit growth of vegetation that can form islands. Cranes are now concentrated primarily in areas where that work has been conducted. The density, however, has raised concerns about the increased risk of disease transmission between sandhill cranes and other birds, especially whooping cranes. A continued shift of birds from west to east and birds staying longer than the three to four weeks they once did, coupled with an increasing sandhill crane population that is two to three times greater than it was in the early 1970s, could further increase density, making the work to restore habitat along the river even more important. But Caven said conservation partners will need to look at where and how the work is being done, as cranes are even abandoning some reaches of the river where habitat has been restored. While some may be tempted to give up on those areas, maintaining stopover habitat there is critical because of the use of those reaches by whooping cranes. "We're probably not restoring areas that are big enough to redistribute the cranes," Caven said. They will also need to look east to insure the habitat the cranes are adopting is maintained. In the two eastern reaches, the character of the river remains good and there is a considerable amount of meadow and prairie. But less than one percent of the land within a half mile of the channel is protected, either through ownership by a conservation organization or through a conservation easement, a pittance compared to the 34 to 67 percent in some other reaches. "Our major concern is sandpits and housing developments," Caven said, noting that conservation easements that would prevent such development while allowing farming and ranching to continue would be invaluable in protecting the habitat. The work along the river isn't important only to cranes. An open, braided river benefi ts other species like whooping cranes and least terns. The large blocks of prairie benefi t prairie chickens, bobolinks, Henslow's sparrows and other upland species. "There's a lot [in this study] of sandhill cranes, but they're really good umbrella species," Caven said. "They're a really good indicator of habitat quality because their presence in high numbers is refl ective of the historic structure of and function of that ecosystem." Sandhill cranes feed in open ground in a snow covered meadow near the Platte River in Kearney County. Meadows are important feeding and loafing habitat for cranes.

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