Laserfiche WebLink
<br /><. <br />^~ <br /> <br />22 <br /> <br />diversity of the wild flock and may be of assistance in evaluating potential inbreeding effects <br />in the future, <br /> <br />Radiotelemetry techniques were first tested on cross-fostered whooping cranes in the RMP <br />(Drewien and Bizeau 1981), Beginning in 1979, flightless young were captured and marked <br />with plastic leg bands to which miniature radio transmitters (45-60 g) were attached, Local <br />movements of the radio-tagged birds were monitored on summering and wintering areas and <br />several individuals were followed during their fall migration between Grays Lake NWR in <br />southeastern Idaho and Monte Vista NWRin south-central Colorado. No adverse effects <br />were noted from capturing, banding, and radio-tagging young whooping cranes (Drewien <br />and Bizeau 1981). <br /> <br />On the basis of these preliminary studies, a cooperative Service-CWS-National Audubon <br />Society radio tracking program was initiated for birds in the AWP to determine various <br />aspects of migration ecology, including habitat characteristics, behavior, and sources of <br />mortality, During each summer 1981-1983,small solar-powered transmitters were placed <br />on several prefledged whooping cranes captured during the routine color-banding operation <br />in WBNP (Kuyt 1979,l!, 1979.!:l, 1992), Data were obtained on three southbound and two <br />northbound migrations, Most information involved the individuals or family groups actually <br />being followed, but data were also accumulated on other migrating whooping cranes <br />encountered during the project. <br /> <br />The successful tracking project resulted in important information concerning migration <br />routes, migration timing, flight methods and speed, stop-over locations and staging areas, <br />habitat use, social behavior, activity budgets, predator/disturbance reactions, and sources of <br />mortality (Howe 1989, Kuyt 1992). Perhaps the most important result obtained from this <br />tracking project has been documenting mortalities on the breeding grounds (wolf predation) <br />(Kuyt et a!. 1981), during migration (power line collisions), and on the wintering grounds <br />(predation and disease). Two of nine radio-marked whooping cranes died within the first 18 <br />months of life as a result of powerline collisions (Kuyt 1992). Similar valuable information <br />has been acquired on migration and behavior of whooping cranes in the RMP (Drewien and <br />Bizeau 1981, Asherin and Drewien 1987, Drewien et al. 1989), <br /> <br />Additional powerline construction, throughout the principal migration corridor, will <br />undoubtedly increase the potential for collision mortalities. Tests of line marking devices, <br />using sandhill cranes as surrogate research species, have identified techniques effective in <br />reducing collisions (Brown and Drewien 1994,l!, 1994.!:l, Morkill and Anderson 1992). Lines <br />should be marked in areas frequently used by whooping cranes. New line corridors should <br />avoid wetlands or other crane use areas. <br /> <br />Miaration Habitat Manaaement And Research: Based on a preponderance of sightings along <br />the central Platte River in Nebraska during 1820-1948,Allen (1952) believed that whooping <br />cranes made that area a major stopover, remaining in the area for some days. In 1978, the <br />U.S. Fish and Wildlife Service designated an 88 km portion of the Platte River in central <br />Nebraska as critical habitat. <br /> <br />As a result of reduced channel width, loss of adjacent wet meadows, and encroachment of <br />the channel by woody vegetation brought on by diversion and storage of water for irrigation <br />