North American Crane Working Group


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Spalding, Marilyn G., Stephen A. Nesbitt, Martin J. Folk, Lee R. McDowell, and Maria A. Sepulveda. Metal consumption by whooping cranes and possible zinc toxicosis. In: Urbanek RP, Stahlecker DW, eds. 1997. Proceedings of the Seventh North American Crane Workshop, 1996 Jan 10-13, Biloxi, Mississippi. Grand Island, NE: North American Crane Working Group. pp. 237-42.


Used by permission of the North American Crane Working Group.


Fourteen captive-reared whooping cranes (Grus americana) were transferred to a pen for soft-release in Florida. Nine were killed by predators within 6 months. We found metal objects in the stomachs of 6 of these 9 either by radiography or at necropsy. All 6 had elevated serum zinc (Zn) concentrations (x = 10.3 ± 2.7 flg/ml, range 7.2-14 .ug/ml) when compared to 3 without metal in their stomachs (X = 2.4 ± 0.92 flg/ml, range 1.6-3.4 J1.g/ml). We observed lethargy, abnormal posture, anemia, and elevated white blood cell counts in 2 cranes at or near the time of elevated serum Zn. The metal was surgically removed from these 2 and they appeared to recover. Metal debris from chain-link fence construction was the primary source of ingested objects.