title: Feather lead concentrations and (207)Pb/(206)Pb ratios reveal lead exposure history of California Condors (Gymnogyps californianus).
abstract: Lead poisoning is a primary factor impeding the survival and recovery of the critically endangered California Condor (Gymnogyps californianus). However, the frequency and magnitude of lead exposure in condors is not well-known in part because most blood lead monitoring occurs biannually, and biannual blood samples capture only approximately 10% of a bird's annual exposure history. We investigated the use of growing feathers from free-flying condors in California to establish a bird's lead exposure history. We show that lead concentration and stable lead isotopic composition analyses of sequential feather sections and concurrently collected blood samples provided a comprehensive history of lead exposure over the 2-4 month period of feather growth. Feather analyses identified exposure events not evident from blood monitoring efforts, and by fitting an empirically derived timeline to actively growing feathers, we were able to estimate the time frame for specific lead exposure events. Our results demonstrate the utility of using sequentially sampled feathers to reconstruct lead exposure history. Since exposure risk in individuals is one determinant of population health, our findings should increase the understanding of population-level effects from lead poisoning in condors; this information may also be helpful for other avian species potentially impacted by lead poisoning.
authors.affiliation: Microbiology and Environmental Toxicology Department, University of California, Santa Cruz, California 95064, USA. myraf@ucsc.edu
authors.forename: M E
authors.initials: ME
authors.lastname: Finkelstein
authors.forename: D
authors.initials: D
authors.lastname: George
authors.forename: S
authors.initials: S
authors.lastname: Scherbinski
authors.forename: R
authors.initials: R
authors.lastname: Gwiazda
authors.forename: M
authors.initials: M
authors.lastname: Johnson
authors.forename: J
authors.initials: J
authors.lastname: Burnett
authors.forename: J
authors.initials: J
authors.lastname: Brandt
authors.forename: S
authors.initials: S
authors.lastname: Lawrey
authors.forename: A P
authors.initials: AP
authors.lastname: Pessier
authors.forename: M
authors.initials: M
authors.lastname: Clark
authors.forename: J
authors.initials: J
authors.lastname: Wynne
authors.forename: J
authors.initials: J
authors.lastname: Grantham
authors.forename: D R
authors.initials: DR
authors.lastname: Smith
mesh_terms: D000818:Animals; D002140:California; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D046093:Falconiformes / Q000097:blood / Q000378:metabolism*; D005241:Feathers / Q000378:metabolism*; D007554:Isotopes; D007854:Lead / Q000097:blood / Q000378:metabolism*; D007855:Lead Poisoning / Q000097:blood; D012621:Seasons; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D007554:Isotopes; D007854:Lead