• California condor recovery: a work in progress

      Wallace, Michael P.; Lamont, Miles M. (Hancock House PublishersToronto, Ontario, Canada. Surrey, BC, Canada., 2014)
    • 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....
    • Hierarchical dominance structure in reintroduced California condors: correlates, consequences, and dynamics

      Sheppard, James; Walenski, Matthew; Wallace, Michael P.; Vargas Velazco, J.J.; Porras, C.; Swaisgood, Ronald R. (2013)
      Populations of reintroduced California condors (Gymnogyps californianus) develop complex social structures and dynamics to maintain stable group cohesion, and birds that do not successfully integrate into group hierarchies have highly impaired survivability. Consequently, improved understanding of condor socioecology is needed to inform conservation management strategies…
    • 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.