• California condor North American studbook (Gymnogyps californianus)

      Mace, Michael E.; (Zoological Society of San DiegoEscondido, CA, 2010)
    • California condor studbook

      Mace, Michael E. (San Diego Zoo GlobalSan Diego: San, 2012)
    • California Condor Studbook

      Mace, Michael E. (Zoological Society of San DiegoSan Diego, 2011)
    • Efforts to restore the California condor to the wild

      Wallace, Michael P. (2012)
      By the early 1980s new studies using radio telemetry and moult patterns to identify individuals indicated that only 21 California condors (Gymnogyps californianus) existed, with five pairs sporadically breeding. With continuous and poorly understood mortality, the decision was made to capture the remaining animals and in 1987 all 27 birds were placed in the protective custody of the San Diego and Los Angeles zoos, at which time the species was considered Extinct in the Wild....
    • Feather lead concentrations and 207Pb/20Ppb ratios reveal lead exposure history of California condors (Gymnogyps californianus)

      Finkelstein, M. E.; George, D.; Scherbinski, S.; Gwiazda, R.; Johnson, M.; Burnett, J.; Brandt, J.; Lawrey, S.; Pessier, Allan P.; Clark, M.; et al. (2010)
      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 ?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.
    • Lead poisoning and the deceptive recovery of the critically endangered California condor

      Finkelstein, M. E.; Doak, D. F.; George, D.; Burnett, J.; Brandt, J.; Church, Molly; Grantham, J.; Smith, D. R. (2012)
      ...California condors were brought to the brink of extinction, in part, because of lead poisoning, and lead poisoning remains a significant threat today. We evaluated individual lead-related health effects, the efficacy of current efforts to prevent lead-caused deaths, and the consequences of any reduction in currently intensive management actions....
    • Patterns of mortality in free-ranging California condors (Gymnogyps californianus)

      Rideout, Bruce; Stalis, Ilse H.; Papendick, Rebecca; Pessier, Alan P.; Puschner, B.; Finkelstien, M.E.; Smith, D.R.; Johnson, M.; Mace, Michael E.; Stroud, R.; et al. (2012)
      We document causes of death in free-ranging California Condors (Gymnogyps californianus) from the inception of the reintroduction program in 1992 through December 2009 to identify current and historic mortality factors that might interfere with establishment of self-sustaining populations in the wild. A total of 135 deaths occurred from October 1992 (the first post-release death) through December 2009, from a maximum population-at-risk of 352 birds, for a cumulative crude mortality rate of 38%. A definitive cause of death was determined for 76 of the 98 submitted cases, 70%(53/76) of which were attributed to anthropogenic causes. Trash ingestion was the most important mortality factor in nestlings (proportional mortality rate [PMR] 73%; 8/11), while lead toxicosis was the most important factor in juveniles (PMR 26%; 13/50) and adults (PMR 67%; 10/15). These results demonstrate that the leading causes of death at all California Condor release sites are anthropogenic. The mortality factors thought to be important in the decline of the historic California Condor population, particularly lead poisoning, remain the most important documented mortality factors today. Without effective mitigation, these factors can be expected to have the same effects on the sustainability of the wild populations as they have in the past.