North American Crane Working Group


Date of this Version


Document Type



Zimorski, S.E., and R.P. Urbanek. The role of retrieval and translocation in a reintroduced population of migratory whooping cranes. In: Hartup, Barry K., ed., Proceedings of the Eleventh North American Crane Workshop, Sep 23-27, 2008, Wisconsin Dells, Wisconsin (Baraboo, WI: North American Crane Working Group, 2010), p. 216.


Reproduced by permission of the North American Crane Working Group.


Beginning in 2001, a reintroduction project was initiated using captive-reared whooping cranes (Grus americana) to establish a migratory flock in eastern North America. From May 2003 to August 2008, 23 of these birds were retrieved and translocated in 15 separate events. These individuals consisted of 14 cranes that had been led to Florida by ultralight aircraft on their first autumn migration (UL) and 9 cranes that had been directly released in autumn in Wisconsin (DAR). Of 104 (86 UL and 18 DAR) reintroduced individuals that eventually departed from their release location, 22% were later retrieved 1-3 times. Lake Michigan posed an effective barrier to northward migrating yearlings, and 8 retrieval events were of birds in Lower Michigan or in other locations that were a direct result of the bird having been in Michigan during their yearling spring and summer. Three events involved DAR birds (n = 8) that were in inappropriate locations during their first autumn migration, and in another event 4 UL birds were translocated within Wisconsin because of inadequate human avoidance behavior. Nine yearlings (6 UL and 3 DAR) in Lower Michigan were not retrieved (retrievals were attempted for only 3 of the birds). The summer location of released birds influenced the location of return in future years. Concentration of this population in the core reintroduction area, where probability of pair formation and association with conspecifics was greatest, became a high project priority. Retrieval and translocation of yearlings to Wisconsin became a critical management tool in the reintroduction. With 1 exception, all translocated birds have successfully returned to the core reintroduction area by 2008, and several have paired and some nested.