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Folk, M.J., J.A. Rodgers Jr., T.A. Dellinger, S.A. Nesbitt, J.M. Parker, M.G. Spalding, S.B. Baynes, M.K. Chappell, and S.T. Schwikert. Status of non-migratory whooping cranes in Florida. 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), pp. 118-123.
We soft-released 289 whooping cranes (Grus americana) into central Florida during 1993-2006 in an effort to establish a non-migratory population. As of September 2008, the population numbered 30 birds (11 pairs), including 12 males and 18 females. Survival and productivity rates have been lower than expected. Males did not survive past 10 years of age, whereas females have lived to at least 15 years of age. Most older males died as a result of predation or from colliding with power lines. We marked power lines and developed a streamlined transmitter to help reduce the number of collisions with the lines. From 68 nests monitored between 1999 and 2008, 31 chicks hatched and 9 fledged. Since 2002, when the first wild chick fledged, 3 wild-fledged birds have died and 1 has gone missing and is presumed dead. Florida has undergone several major droughts since the first nest was initiated in 1999; rainfall and wetland water levels did not meet apparent thresholds necessary for productivity in 6 out of 10 study years. Loss of habitat was an additional concern.