SURVIVAL AND MOVEMENTS OF GREATER SANDHILL CRANES EXPERIMENTALLY RELEASED IN FLORIDA

The potential reintroduction of a population of whooping cranes (Grus americana) in Florida depends on having an effective introduction tech nique. We tested 2 experimental release techniques to evaluate post-re lease survival, dispersal, and the innate predilection to migration in cranes as a preliminary step in the establishment of a non-migrating population of whooping cranes. Thirty-four eggs of migratory greater s andhill cranes (GSHC) (G. canadensis tabida) were exchanged for the cl utches in 23 nests of Florida sandhill cranes (FSHC) (G. c. pratensis) , a non-migratory subspecies; 5 young were fledged from these introduc tions. Concurrently, 27 captive-reared, subadult GSHC were soft-releas ed in the same area of north-central Florida. Movements and survival o f both release groups were assessed through radio telemetry. In genera l, dispersal was similar to normal, subadult FSHC. The experimental bi rds tended to move south in autumn, but did not move north in the spri ng; frequency of southern movements was not different in control and e xperimental groups. Survival differed (P < 0.005) between experimental groups; 56% for captive-reared young (for the first year following re lease) and 39% for foster-reared young (from hatching to leaving natal home range). Our data suggest that captive-rearing and soft-release s hould be used as the primary reintroduction strategy for future releas es of whooping cranes.