A most unusual avian migratory event takes place each .,pring in the Platte River basin of Nebraska between 98 and 102 degrees longitude (Fig. 1). In suitable habitats throughout this area large concentrations of Sandhill Cranes, Crus canadensis, and White-fronted Geese, Anser albifrons, develop and achieve peak populations in mid to late March. This phenomenon is traditional to the migratory habits of specific populations and occurs during the spring movement from wintering grounds in Texas, New Mexico, and Mexico to breeding grounds far to the north in Canada and Alaska. In both species groups of individuals drift in from wintering grounds and numbers increase until as much as 80 percent of that migratory population is concentrated within the basin. Whereas several weeks are required to develop peak numbers, the second lag of the journey northward is a mass movement, taking several days, leaving but a few stragglers behind (Buller and Boeker, 1965; Buller, 1967; Norm Dey, Nebraska Game and Parks, personal communication).
Sharpe, Roger S., "The Origins of Spring Migratory Staging by Sandhill Cranes and White-Fronted Geese" (1978). Biology Faculty Publications. 28.