Condition-dependent reproductive success in bighorn ewes


  • Festa-Bianchet

    1. Groupe de Recherche en Écologie, Nutrition et Énergétique, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1.
    Search for more papers by this author

MarcoFesta-Bianchet E-mail:


Individual bighorn ewes (Ovis canadensis) at 4–14 years of age were 1.5% heavier preceding years when they weaned a lamb than preceding years when their lamb died before weaning. Intra-individual differences in mass between years of successful and unsuccessful reproduction appeared independent of a ewe’s multiyear average mass. Relative mass loss both in the winter before and in the winter after a given repro-ductive episode increased with reproductive success. Long-term monitoring of individual mass and reproductive success is a promising technique to study life histories in capital breeders, because it allows to partially account for differences in reproductive potential.