Patterns of mortality in free-ranging California condors (Gymnogyps californianus)

Bruce A. Rideout, Ilse Stalis, Rebecca Papendick, Allan Pessier, Birgit Puschner, Myra E. Finkelstein, Donald R. Smith, Matthew Johnson, Michael Mace, Richard Stroud, Joseph Brandt, Joe Burnett, Chris Parish, Jim Petterson, Carmel Witte, Cynthia Stringfield, Kathy Orr, Jeff Zuba, Mike Wallace, Jesse Grantham

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


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 selfsustaining populations in the wild. A total of 135 deaths occurred from October 1992 (the first postrelease 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.

Original languageEnglish (US)
Pages (from-to)95-112
Number of pages18
JournalJournal of Wildlife Diseases
Issue number1
StatePublished - Jan 1 2012


  • California condor
  • Cathartidae
  • Lead toxicosis
  • Mortality
  • Pathology
  • Reintroduction

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology


Dive into the research topics of 'Patterns of mortality in free-ranging California condors (Gymnogyps californianus)'. Together they form a unique fingerprint.

Cite this