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 '21 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.

Impacts of Invasive Plants on Sandhill Crane (Grus canadensis) Roosting Habitat

“…These variables were consistent with other efforts (Folk and Tacha 1990); however, they were established at a finer level of detail. For example, the 2005 land cover data set allowed plants to be separated into the two species under consideration, common reed and purple loosestrife.…”

“…The predictor variables considered are summarized in Table 3. The choice of predictor variables used in this study was based on the findings of previous research (Folk and Tacha 1990;Norling et al 1992) and the expert opinion of U.S. Fish and Wildlife Service (USFWS) biologists.…”

“…Three habitat patch categories were tested; early successional river, active river channel, and unvegetated sandbars (Figure 2a), all of which have been shown to impact sandhill crane roosting habitat (Folk and Tacha 1990;Norling et al 1992). The habitat patch variables were calculated by totaling the area of each category, using a moving window with a 50-m radius.…”

“…Changes in hydrology in the Platte River have likely contributed to the expansion of common reed, and as a result could have a negative impact on sandhill crane roosting habitat. Research has examined a wide variety of physical characteristics and has identified those associated with suitable sandhill crane roosting sites (Davis 2003;Folk and Tacha 1990;Norling et al 1992), such as unobstructed views (Folk and Tacha 1990;Norling et al 1992). Such obstructions include plants greater than 1 m in height.…”

Evaluation of nocturnal roost and diurnal sites used by whooping cranes in the Great Plains, United States

“…They accomplished this task by first defining seven metrics based on a conceptual model of resources required by migrating whooping cranes. Many of these metrics were related to perceived safety and security at locations, as have been identified in other efforts for whooping cranes and sandhill cranes (Antigone canadensis) (Armbruster, 1990;Belaire and others, 2014;Folk and Tacha, 1990;Krapu and others, 1984). After identifying metrics, data collected on the central Platte River were used to empirically derive thresholds based on an explicit desire to define places where 90 percent of whooping cranes would likely roost.…”