SANDHILL CRANES AND THE PLATTE RIVER--A CLOSER LOOK

A half million sandhill cranes stop for several weeks in spring in the Central Platte River Valley (CPRV) of Nebraska to obtain key nutrient needs before continuing their spring migration. Using satellite telemetry and other techniques, we and other USGS scientists currently are seeking a detailed understanding of the various facets of the relationship between the midcontinent sandhill crane population and the Platte River. We describe length of time individual radio-marked sandhill cranes spend at the Platte each spring and the role of the Central Platte River Valley in preparing the birds physiologically for migration and reproduction. When the cranes leave the Platte, we monitor their movements throughout the year with the aid of 30 g Platform-Transmitting Terminals attached to plastic leg bands. As a result, we have been able to examine the role of the Platte in meeting the needs of various subpopulations that breed from northern Siberia to eastern Ontario. Also, with radio-telemetry we are assessing the extent that individuals return to the same roost site at the Platte from one year to the next, and factors associated with roost-site selection.