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... o. . ~ I I I I I I I I I I I I SECTIDNTHREE Whooping Crane During spring, recorded stopovers along the Platte River are higher than any other stopover sjte within the species' range (Figure 3-2). Confirmed whooping crane sightings along the Platte River during the spring migration have occurred between March 9 and May 14 (Table 3-2). Fall sightings of whooping cranes are less common than spring sightings along the Platte River (Figure 3-3), and the number of records is less than in critical habitat areas of Kansas and Oklahoma. Fall whooping crane sightings along the Platte River have been as far east as Hamilton County and as far west as Moroll County, Nebraska. Since 1928, the earliest confirmed fall reports of whooping cranes anywhere in Nebraska is October 1. Based on arrival dates at Aransas, however, some whooping cranes likely migrate through the state during the latter part of September. Only three confirmed sightings have occurred in Nebraska after November 10. Four important migrational habitat areas are designated as critical habitat for the whooping crane: Salt Plains National Wildlife Refuge, Oklahoma; Quivira National Wildlife Refuge and Cheyenne Bottoms State Wildlife Area, Kansas; and the Platte River Valley, Nebraska (50 CFR 17.95). The critical habitat of the Platte River is a 3-mile wide, 56-mile long segment between Lexington and Denman, Nebraska (Figure 3-4), including portions of Bridge Segments 6 through 12. The following factors were used by the U.S. Department of the Interior in making the critical habitat determination for the Platte River: 1. The Platte River bottoms provide a dependable source of food, water, and other nutritional or physiological needs for the whooping crane during spring and fall migrations. Insects, crayfish, frogs, small fish, and other small animals as well as some aquatic vegetation and some cereal crops in adjacent croplands appear to be major items taken during the migration period. 2. Under certain flow regimes, the Platte River generally provides whooping cranes with the required open expanse for nightly roosting. The availability of shallow, submerged sand and gravel bars in rivers and lakes appears to be one of the major factors determining whooping crane use of these habitats as roosting sites. Cranes observed during migration are most often found Witll.ll-.l 5ho~ flig..1.t dista..'1CCS oft.l-:le$e \vetland areas. 3. The Platte River provides needed isolation. Whooping cranes do not readily tolerate human disturbances. A human on foot, at distances of over 0.25-mile, can quickly put a crane to flight. 3.4.1 Roost Sites The one common feature of the vast majority of whooping cranes sightings in migration is undisturbed roosting sites. Whooping crane roost sites in the study area include river channels that have a wide expanse of water and shallow, submerged sandbars. Water characteristics apparently contribute to site security. An evaluation often known whooping crane riverine roosting sites identified the following characteristics (Johnson and Temple 1980; FWS 1981; Johnson 1982): L Wide channel, nine often roost sites measured were between 510 and 1,200 feet wide UlIS....,. M.JwantQJJfr fetIenI.~ 3-6 68FOO!mB6OO'r1.doc 61211999(9:52 AM)lURSGWCFS12