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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Wildlife and Fisheries Science

First Advisor

Leigh H. Fredrickson


sandhill cranes, Rocky Mountains, populations, food, habitat


The goal of this study was to gain insights into the type, abundance, biomass, and distribution of below-ground foods used by RMP cranes in agricultural fields and wetlands across six annual cycle events in 2006 and 2007 (wintering, spring staging, spring stopover, breeding, post-breeding, and fall staging). Below-ground foods were sampled in sandhill crane foraging habitats at three United States Fish and Wildlife Service (USFWS) National Wildlife Refuges (NWR) in the Intermountain West where these life cycle events occur. Grays Lake NWR in Idaho is a traditional RMP crane breeding area; Monte Vista NWR in the San Luis Valley in Colorado is an important crane stopover site during spring and fall migration; and Bosque del Apache NWR in New Mexico is a crane wintering site in the floodplain of the Rio Grande River. Sandhill cranes (Grus canadensis) have been present on the North American landscape for over 4 million years and have adapted to wetlands for nesting, feeding, and roosting. Large-scale wetland loss across the continent makes the Intermountain West one of the few remaining areas where greater sandhill cranes can carry out a successful annual cycle because of the presence of remnant wetlands. The Rocky Mountain Population (RMP) adapted to a mosaic of wetland habitats resulting from a unique interaction of climate and geography. Although cranes have discrete movement and migration patterns, annual life cycle events have overlapping energetic and nutritional requirements that enable the species to survive and reproduce. Crane management by wildlife agencies has relied on agricultural approaches even though certain life history stages require nutritional needs that cannot be supplied by agricultural foods. Results of this study indicate below-ground foods are a substantial part of the nutritional resources available in wetlands across the Intermountain West. Natural wetlands provide a greater diversity, abundance, and biomass of below-ground invertebrate and plant foods than agricultural habitats. Distribution, abundance, and biomass of below-ground foods of value to RMP cranes vary spatially and temporally with geomorphic setting and abiotic processes. These nutritionally valuable foods are commonly available when above ground foods are less so, increasing their value to cranes in fall, winter, and early spring.

Library of Congress Subject Headings

Greater sandhill crane -- Food -- Rocky Mountains
Great sandhill crane -- Habitat -- Rocky Mountains


Includes bibliographical references (page 105-112)



Number of Pages



South Dakota State University


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