Date of this Version
Miller, J.L., M.G. Spalding, and M.J. Folk. Leg problems and power line interactions in the Florida resident flock of 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), pp. 156-165.
We retrospectively reviewed a database with over 1,800 health entries from 296 captive-reared whooping cranes (Grus americana) released in central Florida and 10 wild-fledged chicks from 1992 to 2007. Fifty percent of the study population (n = 306) had 1 or more leg problems that were placed into 4 broad categories: power line interactions (n = 39), other trauma (n = 94), deformities (n = 43), and miscellaneous conditions (n = 106). More males (n = 26, 67%) had power line interactions than females (n = 13, 33%). The majority of these 39 birds died (57%), while the rest recovered from an injury (20%), went missing (7%), or survived with no apparent injury (16%). Twenty-two of the 44 (50%) recorded power line strikes involved the leg-mounted transmitter. Most minor leg problems in the other trauma category were observed at arrival or quarantine examinations; no major injuries occurred as a result of >800 handling or capture events. Birds arriving in Florida with toe deformities, short legs, or a leg rotation had no difference in survival or reproductive value when compared to the general population. All categories except for deformities contained birds with injuries associated with mortality. The most mortality related injuries were a result of power line interactions. Among the 149 birds with leg problems, 44 cranes (29%, 14% of all birds) had injuries sufficient enough to be associated with mortality. Birds that survived leg injuries lived longer than birds with no previous injury prior to death.