U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2005-3029 

April 2005

Assessing Sandhill Crane Roosting Habitat

along the Platte River, Nebraska

Over the last century, upstream waterresource development has affected 

the delivery of water and sediment to 

the central Platte River by eliminating 

high flows from the river and decreasing 

the sediment supply (Williams, 1978; 

Eschner and others, 1983). These changes 

have resulted in channel incision and 

vegetation encroachment along the riparian corridor. The once braided, wide, and 

shallow channels of the Platte have narrowed and deepened, and the sediment in 

these channels has become significantly 

coarser (Kinzel and others, 1999). During 

the same period of time, wetland meadow 

habitat, which provides a key source of 

protein for cranes, has decreased (Sidle 

and others, 1989). The changes in river 

morphology and distribution of wetland 

meadows are believed to have altered the 

nocturnal roosting habitat used by cranes 

(U.S. Fish and Wildlife Service, 1981; 

Krapu and others, 1984; Faanes and 

LeValley, 1993).

Video Images of Roosting Cranes

Cranes roost in the river at night, arriving 

at their roosts approximately one hour 

after sunset and leaving before sunrise. 

Synoptic surveys of roosting cranes were 

conducted at night by using an aerial 

thermal infrared video system. The video 

images were used in a geographical information system (GIS) to produce a map 

of sandhill crane roosting areas along the 

130 kilometers of river between Lexington and Grand Island, Nebraska (Kinzel 

and others, 2001). Video was collected 

from high altitudes (~1200 meters above 

the river) to resolve roosting flocks of 

sandhill cranes across the entire width of 

channels along the central Platte River 

and at low altitudes (~300 meters above 

the river) to resolve individual sandhill 

cranes. Images from low altitude are used 

to compute the spatial density of the birds 

within the roosting areas. Estimates are 

made of the crane population by multiplying the roost areas and the spatial 

densities. By applying this methodology, the number of cranes roosting in the 

central Platte River during the 2000, 2001 

and 2002 infrared surveys were 552,000, 

488,000, and 486,000 birds, respectively. 

The highest concentration of sandhill 

cranes occurs near the National Audubon 

Society’s Rowe Sanctuary.

(Photograph courtesy of P. Tebbel, Rowe Sanctuary)

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Each spring approximately 500,000 sandhill cranes and some endangered whooping cranes use the Central Platte River Valley in Nebraska 

as a staging habitat during their migration north to breeding and nesting 

grounds in Canada, Alaska, and the Siberian Arctic. Over the last century 

changes in the flow of the river have altered the river channels and the 

distribution of roost sites. USGS researchers studied linkages between 

water flow, sediment supply, channel morphology, and preferred sites for 

crane roosting. These results are useful for estimating crane populations 

and for providing resource managers with techniques to understand 

crane habitats.

In cooperation with Federal, State, 

and local stakeholders, the U.S. Geological Survey (USGS) initiated the 

Platte River Program (http://mcmcweb.

er.usgs.gov/platte/), a multidisciplinary 

effort. As part of the study, scientists 

in the National Research Program 

(NRP) in the hydrological sciences 

focused their research efforts on 

understanding how changes in water 

flow and sediment transport affect 

roosting sites for cranes. This study 

provides information to evaluate the 

effectiveness of management actions 

taken to improve the availability of 

roosting habitat for cranes, such 

as creation of wetland meadows, 

vegetation clearing and river flow 

manipulation.

During the spring, the cranes roost in the 

central Platte River from dusk until dawn. 
Sandbar Morphology and 

Hydraulic Modeling

The next part of the study was to relate 

the observed crane roosting sites to river 

morphology and hydraulics in the reach 

of the river near the Rowe Sanctuary. A 

survey-grade global positioning system 

was used to produce a detailed topographic map of the river channel, islands, 

sandbars and banks. The topographic 

map was used in a multi-dimensional 

hydraulic model to obtain river depths 

and velocities for specified discharges. 

The hydraulic modeling was carried out 

with the USGS-developed public domain 

Multi-dimensional Surface Water Modeling System (MD_SWMS, available 

at http://wwwbrr.cr.usgs.gov/projects/

SW_Math_mod/OpModels/MD_SWMS/

index.htm). A vertically averaged twodimensional model was used to predict 

the spatial distribution of water depth 

and velocity along the study reach for 

selected stream flows (figure below).

The crane roost maps defined from the 

infrared video were overlain on the flow 

modeling results to identify the ranges in 

depth and velocity preferred by roosting 

cranes (figure right). Cranes generally 

prefer to roost in water depths less than 

0.40 meters with velocities less than 0.70 

meters per second. By examining these 

results at several stream flows, it was 

determined that the largest amount of 

available roosting habitat occurs at the 

Rowe Sanctuary when the stream flow in 

this channel is about 37 cubic meters per 

second. These model results were computed by assuming the riverbed is fixed 

and immobile. In actuality, at higher 

stream flows, sand could be deposited on 

the submerged sandbars, increasing their 

References

Eschner, T.R., Hadley, R.F., and Crowley, K.D., 1983, 

Hydrologic and morphologic changes in the channels 

of the Platte River basin in Colorado, Wyoming and 

Nebraska: A historical perspective: U.S. Geological Survey Professional Paper 1277-A, Reston, Virginia, 39 pp.

Faanes, C.A., and LeValley, M.J., 1993, Is the distribution 

of sandhill cranes on the Platte River changing?: Great 

Plains Research 3, p. 297–304.

Kinzel, P.J., Nelson, J.M., Parker, R.S., Bennett, J.P., and 

Topping, D.J., 1999, Grain-size evolution of the Platte 

River, 1931–1998, in Proceedings of the 10th Platte 

River Basin Ecosystem Symposium, February 23–24, 

1999, Kearney, Nebraska, p. 9–14.

Kinzel, P.J., Parker, R.S., Nelson, J.M., Starbuck, M., and 

Davis, L., 2001, Mapping sandhill crane roost sites 

along the central Platte River using aerial infrared videography, in Proceedings of the 11th Platte River Basin 

Ecosystem Symposium, February 27, 2001 Kearney, 

Nebraska, p. 8.

Krapu, G.L., Facey, D.E., Fritzell, E.K., and Johnson, 

D.H., 1984, Habitat use by migrant sandhill cranes in 

Nebraska: Journal of Wildlife Management, v. 48, no. 

2, p. 407–417.

Sidle, J.G., Miller, E.D., and Currier, P.J., 1989, Changing 

habitats in the Platte River Valley of Nebraska: Prairie 

Naturalist, v. 21, no. 2, p. 91–104.

U.S. Fish and Wildlife Service, 1981, The Platte River 

Ecology Study: U.S. Fish and Wildlife Service Special 

Scientific Report, Jamestown, North Dakota. 187 pp. 

Williams, G.P., 1978, The case of the shrinking channels—

The North Platte and Platte Rivers in Nebraska: U.S. 

Geological Survey Circular 781, Arlington, Virginia, 

48 pp.

For Additional Information

Chief Scientist for Hydrology 

U.S. Geological Survey

436 National Center

Reston, Virginia 20192

Low altitude aerial image of individual sandhill 

cranes roosting in the Platte River. The land 

appears light gray, the water dark gray, and 

the roosting cranes as small gray dots.

Output from modeling showing water depth and velocity distributions along the Rowe Sanctuary 

in the Platte River for a stream flow of 57 cubic meters per second. 

P.J. Kinzel, J.M. Nelson, and R.S. Parker, 

USGS, Denver, Colorado

elevation, which may increase the quantity of available habitat. Investigating 

these effects would require modifying the 

model to incorporate sediment transport 

and verifying what influence this might 

have on the sandbars.

The results of this research provide a 

direct linkage between crane roosting 

habitat and river flows in the Platte. 

The methodology described shows how 

remote sensing, hydraulic modeling, 

and habitat assessments can be used to 

develop scientific tools for evaluating the 

efficacy of management actions. 

Information about other projects 

underway in the National Research 

Program can be found on the Internet 

at http://water.usgs.gov/nrp/

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Printed on recycled paper

Histogram showing the ranges of depths and 

velocities used by roosting cranes in the Rowe 

Sanctuary study reach.