George F. Gee

POST-RELEASE SURVIVAL OF HAND-REARED AND PARENT-REARED MISSISSIPPI SANDHILL CRANES

Abstract The Mississippi Sandhill Crane (Grus canadensis pulla) reintroduction program is the largest crane reintroduction effort in the world. Here we report on a 4-year experiment in which we compared post-release survival rates of 56 hand-reared and 76 parent-reared Mississippi Sandhill Cranes. First-year survival was 80%. Surprisingly, hand-reared cranes survived better than parent-reared birds, and the highest survival rates were for hand-reared juveniles released in mixed cohorts with parent-reared birds. Mixing improved survival most for parent-reared birds released with hand-reared birds. These results demonstrate that hand-rearing can produce birds which survive at least as well as parent-reared birds and that improved survival results from mixing hand-reared and parent-reared birds.

Motorized Migrations: the Future or Mere Fantasy?

Abstract In 15 experiments from 1993 to 2002, we led cranes, geese, and swans on their first southward migration with either ultralight aircraft or vehicles on the ground. These experiments reveal that large birds can be readily trained to follow, and most will return north (and south) in subsequent migrations unassisted. These techniques can be used to teach birds new (or forgotten) migration paths. Although we are constantly improving our training techniques, we now have an operational program that can be broadly applied to those species whose juveniles learn migration routes from their parents.