Habitat suitability of historical Mississippi sandhill crane nest sites 1991-2022

Certain areas of Mississippi Sandhill Crane National Wildlife Refuge have consistently produced more Mississippi sandhill crane nests and chicks than others, even as the crane pair nesting in those areas have changed. Understanding the drivers of this pattern is an important step toward achieving the goal of a self-sustaining wild Mississippi sandhill crane population. By adapting a Habitat Suitability Index (HSI) for Florida sandhill cranes to Mississippi sandhill cranes, we examined whether differential habitat suitability of nest sites explained the historical variation in nesting production across the refuge. 
Between 1991 – 2022, mean HSI of geolocated nest sites (n = 554, X = 0.52) was significantly higher than that of an equal number of random points across the refuge (X = 0.36). This indicates that our HSI model corresponds to historical nest site choice. However, fledging rate as measured by number of chicks surviving to fledge divided by number of nests did not differ between high and low HSI nest sites, suggesting that factors outside of habitat suitability contribute to chick survival.

DOI: 10.3996/btp46233