Reproductive Success and Survival in the Eastern Population of Sandhill Cranes

The Eastern Population (EP) of Greater Sandhill Cranes (Grus canadensis tabida) has demonstrated an impressive recovery since the population’s historic low circa the 1930s (e.g. ≈25 breeding pairs documented in Wisconsin; Henika 1936, Meine and Archibald 1996). At present, the EP perhaps numbers more than 70,000 birds (Kruse and Dubovsky 2015) and interest in harvest for recreation and to mitigate crop depredation has come to the forefront of discussions on the population’s management. The Management Plan for the Eastern Population of Sandhill Cranes (2010) has proposed a harvest-management strategy based on fall surveys to monitor the population and maintain running three-year average indices above 30,000 cranes (Ad Hoc Eastern Population Sandhill Crane Committee 2010). While precedents set by the harvest of the Mid-Continent Population (MCP) and Rocky Mountain Population (RMP) of Sandhill Cranes support this approach, the landscape within the EP’s range is far more varied than the landscapes in the MCP and RMP ranges and continues to be rapidly urbanized (Fig. 1). If cranes are able to thrive in these urbanizing landscapes it is likely that the EP will continue to increase, perhaps mirroring the population trajectory of the Giant Canada Goose throughout the Midwest in the last 33 years (17.5% per year; Sauer et al. 2011). However, there remain several knowledge gaps in the demographics of the EP including landscapedependent reproductive success and juvenile and adult survival (e.g. two studies published on reproductive success in or near urban environments; Dwyer and Tanner 1992, Toland 1999). Evaluating these vital rates in different landscapes of the EP’s range and at different population densities is essential to refining models of population growth and abundance under different land-use and management scenarios (e.g. urban sprawl and EP harvest).