Behavioral Ecology and Sociobiology

, Volume 67, Issue 8, pp 1227–1238

Hierarchical dominance structure in reintroduced California condors: correlates, consequences, and dynamics

  • James K. Sheppard
  • Matthew Walenski
  • Michael P. Wallace
  • Juan J. Vargas Velazco
  • Catalina Porras
  • Ronald R. Swaisgood
Original Paper

DOI: 10.1007/s00265-013-1550-5

Cite this article as:
Sheppard, J.K., Walenski, M., Wallace, M.P. et al. Behav Ecol Sociobiol (2013) 67: 1227. doi:10.1007/s00265-013-1550-5

Abstract

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. We report on the dominance structure of free-ranging condors and identify the causes and consequences of rank in condor populations by matching social status with the behavioral and physical correlates of individual birds. We characterized the hierarchical social structure of wild condor populations as mildly linear, despotic, and dynamic. Condor social groups were not egalitarian and dominance hierarchies regulated competitive access to food resources. Absence of kin-based social groups also indicated that condor social structure is individualistic. Agonistic interactions among condors were strongly unidirectional, but the overall linearity and steepness of their hierarchies was low. Although one aggressive male maintained the highest dominance rank across the 3-year observation period, there was considerable fluidity in social status among condors within middle and lower rank orders. Older condors were more dominant than younger birds and younger males supplanted older females over time to achieve higher status. Dominance rank did not predict the amount of time that a bird spent feeding at a carcass or the frequency that a bird was interrupted while feeding. Thus, younger, less dominant birds are able to obtain sufficient nutrition in wild social populations.

Keywords

California condor Socioecology Dominance hierarchy Reintroduction 

Supplementary material

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • James K. Sheppard
    • 1
    • 4
  • Matthew Walenski
    • 2
    • 4
  • Michael P. Wallace
    • 1
    • 4
  • Juan J. Vargas Velazco
    • 3
    • 4
  • Catalina Porras
    • 3
    • 4
  • Ronald R. Swaisgood
    • 1
    • 4
  1. 1.San Diego Zoo Institute for Conservation ResearchEscondidoUSA
  2. 2.University of California San Diego/San Diego State UniversityEscondidoUSA
  3. 3.WildCoast/CostaSalvajeEnsenadaMexico
  4. 4.Applied Animal Ecology DivisionSan Diego Zoo Institute for Conservation ResearchEscondidoUSA

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