A sandhill is a type of ecological community or xeric wildfire-maintained ecosystem. It is not the same as a sand dune.

Sandhill Crane Abundance and Nesting Ecology at Grays Lake, Idaho
Effects of fire on sandhill herbs: nutrients, mycorrhizae, and biomass allocation
Distribution and Abundance of Sandhill Cranes Wintering in Western Texas
The Origin and Successional Relationship of Sandhill Vegetation and Sand-Pine Scrub
Fire and the Dynamic Relationship between Florida Sandhill and Sand Pine Scrub Vegetation
Fire and the Florida Sandhill Herpetofaunal Community: With Special Attention to Responses of Cnemidophorus sexlineatus
Factors Influencing Nest Success of Greater Sandhill Cranes at Malheur National Wildlife Refuge, Oregon
Nesting Ecology of Greater Sandhill Cranes (Grus canadensis tabida) in Riparian and Palustrine Wetlands of Eastern Idaho
Thermal, metabolic, hygric and ventilatory physiology of the sandhill dunnart ( Sminthopsis psammophila ; Marsupialia, Dasyuridae)
Effects of Imperata cylindrica (L.) Beauv. (Cogongrass) invasion on fire regime in Florida Sandhill (USA)