Chlorinated Hydrocarbon Pollutants in Alaskan Gyrfalcons and Their Prey

Walker, Wayman

Analyses of biopsy fat samples and addled eggs of Gyrfalcons (Falco rusticolus) and selected prey items collected during 1970 and 1971 from the Seward Peninsula, Alaska show that all samples contained both industrial and agricultural contaminants. A pathway of aerial transport to this remote arctic ecosystem is indicated. Geometric mean levels of DDE, the principal insecticide derivative in both the eggs and fat of Gyrfalcons, are 20 ppm, lipid basis. PCB concentrations are 2-3 times higher, and are significantly correlated with DDE levels in both eggs and fat; the mean ratio of PCB/DDE is 3.0. A similar ratio was found in ptarmigan (Lagopus sp.), the principal prey species, indicating similar movement of these pollutants within this arctic food web. Resident arctic species utilized as prey contain low whole body residue levels, less than 0.5 ppm DDE, lipid basis. The calculated body content of pollutant residues in several Gyrfalcons indicates burdens could not result from resident prey alone but are attributed to the higher residue levels in migratory prey species. Whole body DDE residues were 5.0 ppm in Long-tailed Jaegers (Stercorarias longicaudus) and 50.0 ppm in Golden Plovers (Pluvialis dominica) and Whimbrels (Numenius phaeopus), lipid basis. No significant thinning of Gyrfalcon eggshells was found. Unlike some populations of other species of the genus Falco in North America, this population of Alaskan Gyrfalcons does not appear to be endangered by organochlorine contamination.-Department of Biological Sciences, University of Alaska, Fairbanks, Alaska 99701. Present address: University of California, Bodega Marine Laboratory, Bodega Bay, California 94923. Accepted 26 June 1975.

Chlorinated Hydrocarbon Pollutants in Alaskan Gyrfalcons and Their Prey

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