Species Recovery Objectives for Four Target Species in the Central and Lower Platte River

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B. WHOOPING CRANE B.I. Existing Recovery Plan Goals and Objectives The goal in the existing Whooping Crane Recovery Plan50 for the Aransas/Wood Buffalo Population (AWP) is that the minimum viable population for the AWP is 1000 individuals, including 250 breeding pairs, sustained for a minimum of a decade before being downlisted to threatened status. This population winters at the Aransas National Wildlife Refuge and adjacent areas in Texas and nests in the Northwest Territories and adjacent areas of Alberta, Canada primarily at Wood Buffalo National Park. During spring and fall, whooping cranes in the AWP stop along the Platte River in Nebraska, as well as other locations along their migration pathway. The current Recovery Plan stipulates the Platte River as one location needed for maintaining suitable roosting habitat used by migrating whooping cranes by ensuring adequate flows that provide quality roosting habitat and that are necessary for scouring invading vegetation from the riverbed. The U.S. and Canadian Recovery Plans are being updated and combined to eliminate duplication and to reflect the two nation approach. There are several specific references to the Platte River in the 2001 draft version of the new Whooping Crane Recovery Plan. These refer to protecting habitat and managing vegetation and identify the Platte River as a location where suitable stopover habitat is needed for migrating whooping cranes. B.Z. Habitat Limitations on the Central Platte River Based on a preponderance of sightings along the Platte River in Nebraska during 1820 to 1948, whooping cranes made the Platte River a major stopover.51 During the spring, recorded stopovers along the Platte River are higher than any other stopover site within the species' range. Confirmed whooping crane sightings along the Platte River during the spring migration have occurred between February 15 and May 23.52 In the AWP flyway, roosting sites on riverine areas by whooping cranes were common only in Nebraska, primarily on the Platte, Niobrara, Middle Loup, and North Loup Rivers. 53 The higher use of riverine roosts in Nebraska may be related to the relatively unique geomorphic characteristics of rivers there, which include shallow, relatively slow- moving channel flows and sand bars with little vegetative cover. Numerous studies and articles have documented the physical changes to the Platte River since the late 1800's and resulting habitat loss for whooping cranes as well as 50 Department of the Interior, U.S. Fish and Wildlife Service, Whooping Crane Recovery Plan, February 11, 1994. 51 Allen, R P. 1952. The whooping crane. National Audubon Society Resource Report 3, 246 pp. 52 U. S. Fish and Wildlife Service. Unpublished data 53 Austin, Jane E. and Amy L. Richert. May 2001. A Comprehensive Review of Observational and Site Evaluation Data of Migrant Whooping Cranes in the United States, 1943 -99. 18