Sandhill Crane Roost Site Characteristics in the North Platte River Valley

Abstract

We documented sandhill crane (Grus canadensis) roost site characteristics in the North Platte River Valley (NPRV) of Nebraska in riverine and semipermanent palustrine wetlands from late February through mid-April in 1988 and 1989. Crane roost sites in the river were located closer to visual obstructions, in narrower channels, and in a wider range of water depths than determined previously in the Platte River. Cranes roosted in semipermanent wetlands where widths were _12 m, water depths were 5.0-24.4 cm, and distance to shore was _1 m. Based on the estimated peak number of sandhill cranes and roosting capacity estimates, availability of roosting habitat was not limiting use of the NPRV by cranes. North Platte river flows should be maintained to provide channel widths _48 m and water depths 521 cm for roosting cranes. Temporary (wet meadow) and semipermanent palustrine wetlands adjacent to the river should be preserved to provide important diurnal and nocturnal crane habitat. J. WILDL. MANAGE. 54(3):480-486 The North Platte and Platte River valleys of Nebraska are the primary spring staging areas for the midcontinental population of sandhill cranes (Benning and Johnson 1987). Cranes are dependent upon these valleys to provide high energy foods (especially corn) necessary to accumulate lipid reserves for use in nesting areas (Krapu et al. 1985, Tacha et al. 1987). Loss of grasslands and wetlands to agricultural and commercial development has altered staging habitat of sandhill cranes (Lewis et al. 1977, Currier and Ziewitz 1987). Flow reductions in the rivers allowed encroachment of woody vegetation on sandbars used by cranes for roosting. Current management of crane roosting habitat includes maintenance of water flows and costly mechanical removal of woody vegetation (Lingle 1982). Iverson et al. (1987) found up to 67,500 (45% of total) cranes using off-river temporary and semipermanent wetland roost sites in the North Platte River Valley (NPRV) and recommended the preservation of existing sites and development of additional off-river roost sites. However, no studies of roost site selection have been conducted in the NPRV. Our objectives were to determine factors associated with crane use and selection of river and adjacent wetland roosts and to estimate the roosting capacity of the NPRV. We thank G. A. Wingfield of the Nebraska Game and Parks Commission and P. McDonald of the U.S. Fish and Wildlife Service (USFWS) for providing valuable assistance in Nebraska. Landowners in the NPRV granted access to their property. P. A. Vohs and A. Woolf reviewed the manuscript. This study was funded by USFWS Purchase Orders 64412-00302-88 and 64412-8900026 and the Cooperative Wildlife Research Laboratory, Southern Illinois University at Carbondale (SIUC). Additional support was obtained from the Department of Zoology and the Graduate School at SIUC.