Overwintering Sandhill Cranes (Grus canadensis) in Nebraska, USA

Over half a million Sandhill Cranes (Grus canadensis) migrate through Nebraska, USA, each autumn and spring, but only a few cranes have been reported in Nebraska during winter. In early winter of 2011, however, an estimated 4,000-5,000 Sandhill Cranes were observed in south-central Nebraska along the Platte River. At that time, we initiated a study to search for and document Sandhill Cranes within the Platte River Valley across three winters and relate winter crane observations for the recent period to historical late autumn, winter, and early spring sightings in Nebraska documented by citizen observers for a century. We observed thousands of Sandhill Cranes along the Platte River in winters 2011-2012 and 2012-2013, but none in 2013-2014. Winters 2011-2012 and 2012-2013 were notable for a combination of mild conditions in Nebraska coupled with severe to exceptional drought in the southern United States and northern Mexico at traditional wintering areas for cranes. Analysis of historical observations indicates such large numbers of Sandhill Cranes have not been documented previously during winter in Nebraska, with the exception of 5,000 cranes near Grand Island, Nebraska, on 15 December 1990 that were not reported again following an arctic blast 2-3 days after the sighting. Reported dates of first spring arrivals have shifted over time, with Sandhill Cranes returning progressively earlier in spring in more recent years. If Sandhill Cranes continue to overwinter and/or arrive earlier in spring, there may be consequences for inter-species interactions with migratory waterfowl, such as competition for waste grains or transmission of disease, within the Platte River Valley, as well as for the timing of habitat-management activities. Ongoing monitoring of cranes during winter and early spring will track these patterns to better inform managers of habitat and food resources to help meet the species' needs.