These birds prefer roosting in areas where the channel is at least 150 m wide, and strongly avoid river channels narrower than 50 m. The loss of about two-thirds of the original roosting habitat between Kingsley Dam and Grand Island has caused crowding at remaining roost sites, thereby increasing crane susceptibility to catastrophic losses from natural forces, particularly severe storms and disease. Native grasslands, river channel, and cropland each serve a vital role in maintaining sandhill crane use of the Platte and North Platte River Valleys. Both native grassland and channel habitats are threatened by declining flows. The rapid rate of attrition of native meadows, where cranes obtain much of their protein and calcium, poses an immediate concern.
Prompt action is needed to protect key grassland tracts near the channel.
Crane requirements are well suited to a habitat maintenance plan that protects tracts of moderate to small size spaced a few miles apart along those reaches of the two Rivers that cranes still inhabit, instead of creating a large refuge near Grand Island as originally proposed. Additional protection, possibly through easements, will be needed to maintain existing land use practices on other native grassland tracts near the channel between the managed reserves. Maintenance of an unobstructed river channel width of 150 m at sites within existing staging areas is adequate to satisfy roost-site requirements of the sandhill crane population during the staging period.